Annual Report for 2010/11 and Forward Programme - Sellafield Ltd

Particles in the EnvironmentAnnual Report for 2010/11and Forward ProgrammeJune 2011© Nuclear Decommissioning Authority 2011

SSEM/2011/4730 June 2011Particles in the Environment Annual Report 2010/11Purpose of this reportThis report details the progress that has been made during the 2010/11 financial year on theunderstanding of the nature and potential health risk posed by radioactive particles in theEnvironment. It sets out the aims and objectives for the project and provides the programmeof future work that Sellafield Ltd believes will meet these objectives.© Nuclear Decommissioning Authority 2011. 1

SSEM/2011/4730 June 2011ContentsPurpose of this report .............................................................................................. 1Contents.................................................................................................................... 2List of Tables ............................................................................................................ 4List of Figures........................................................................................................... 41. Introduction........................................................................................................... 62. Background........................................................................................................... 72.1 Origin of the large area beach monitoring programme ............................................72.2 Beach monitoring methods.........................................................................................92.3 Beach monitoring findings to date ...........................................................................102.3.1 Locations ...............................................................................................................102.3.2 Find rates...............................................................................................................102.3.3 Find sizes ..............................................................................................................112.3.4 Find classification ..................................................................................................122.3.4.1 Alpha and Beta-rich ........................................................................................122.3.4.2 Alpha-rich .......................................................................................................122.3.4.3 Beta-rich .........................................................................................................122.3.4.3 60 Co rich..........................................................................................................122.3.5 Analysis of finds.....................................................................................................132.4 Sources and Pathways of beach finds.....................................................................132.5 Offshore monitoring...................................................................................................152.6 Risk Assessment........................................................................................................153. Progress during 2010/11.................................................................................... 173.1 Beach Monitoring 2010/11 ........................................................................................173.1.1 Introduction............................................................................................................173.1.2 Beach monitoring programme specification for 2010/11 .......................................173.1.3. Achievement of the 2010/11 beach monitoring programme.................................173.1.3.1 Detection capability of radionuclide populations...........................................173.1.3.2 Area coverage ................................................................................................183.1.4 Beach Finds..........................................................................................................193.1.4.1 Particles and Stones.......................................................................................193.1.4.2 Geographic distribution of finds ......................................................................233.1.4.3 Find rates per hectare ....................................................................................233.1.4.4. Find Classification .........................................................................................263.1.5 Risks from particles found in the environment.......................................................323.1.6 Conclusions...........................................................................................................323.2 Find Analysis and Statistics......................................................................................333.2.1 Introduction............................................................................................................333.2.2 What has been achieved with this analytical data? ...............................................343.2.2.1 Key Findings from Sellafield Ltd Analyses .....................................................343.2.2.2 Key Findings from External Analyses Contracts ............................................533.2.2.3 Key Findings from GIS Analysis .....................................................................563.2.2.4 Key Findings from Statistical Techniques Analyses .......................................593.2.3 Analysis Conclusions............................................................................................633.3 Offshore Monitoring...................................................................................................643.3.1 Hydrodynamic Modelling Contract.........................................................................643.3.2 Progress on analysis and interpretation of existing swath bathymetry data..........653.3.3 Progress on measurements of bed shear stress in the vicinity of the Sellafielddischarge pipeline...........................................................................................................673.3.4 Progress on the literature review of airborne transport of particles in the Cumbrianbeach environment.........................................................................................................713.4 Monitoring R&D: Evaluation of Airborne Gamma Spectrometry...........................73© Nuclear Decommissioning Authority 2011. 2

SSEM/2011/4730 June 20114. Regulator and Stakeholder engagement.......................................................... 754.1 General Engagement with the Environment Agency..............................................754.2 Multi-Agency Workshop ............................................................................................764.3 COMARE .....................................................................................................................764.4 Sellafield Seabed Monitoring Working Group .........................................................764.5 Local stakeholders.....................................................................................................775. Health Risk Assessment.................................................................................... 785.1 Health Protection Agency assessment ....................................................................785.2 Uncertainty and recommendations for future work................................................795.3 Risks to workers.........................................................................................................805.3.1 Nuvia operations....................................................................................................805.3.2 Inhalation...............................................................................................................815.3.3 Ingestion................................................................................................................815.3.4 Skin contact and wounds.......................................................................................825.3.5 Reassurance by monitoring for internal uptake .....................................................825.3.6 Potential of exposure to the public ........................................................................825.4 Nuvia dosimetry investigation ..................................................................................826. Aims and Objectives .......................................................................................... 846.1 Introducing the requirement for large area beach monitoring...............................846.2 Beach monitoring programme review......................................................................846.3 Developing the approach for offshore monitoring..................................................856.4 Developing aims and objectives for the particles in the environment workprogramme........................................................................................................................866.5 Primary Questions and their Grouping ....................................................................887. Programme of work for 2011/12 ........................................................................ 957.1 2011/12 Beach Monitoring Programme ....................................................................957.2 Application of BAT for beach monitoring ..............................................................1047.2.1 Introduction..........................................................................................................1047.2.2 Beach monitoring detection equipment ...............................................................1047.2.3 Consistent approach for statistical interpretation.................................................1067.2.4 Monitoring speed.................................................................................................1067.2.5 Daily overlap of monitoring area..........................................................................1067.2.6 Strandline monitoring...........................................................................................1077.2.7 Alternative monitoring methods...........................................................................1077.3 Offshore Monitoring for 2011/12 .............................................................................1077.3.1 Continued dialogue with Dounreay Site Restoration Ltd.....................................1077.3.2 DSRL ROV Trial ..................................................................................................1087.3.3 EA Grab Sampling...............................................................................................1087.3.4 Developing the forward programme for offshore monitoring ...............................1097.4 Future Beach Monitoring Assessment Work Programme....................................1137.5 Summary of costs ....................................................................................................1138. Programme of Works ....................................................................................... 115Appendix 1 2010/11 Beach Monitoring Coverage MapsAppendix 2 Interpretation of swath bathymetry in the Eastern Irish Sea for SellafieldLtdAppendix 3 Currents at the Sellafield Ltd Pipeline: June 2010-February 2011Appendix 4 Modelling Gamma Spectrometry Systems for use in Beach Monitoringnear SellafieldAppendix 5 Information sent to EA in support of a 150 ha beach monitoringprogramme© Nuclear Decommissioning Authority 2011. 3

SSEM/2011/4730 June 2011List of TablesTable 2.1. Beach area specified in the CEAR and monitored each year .................................9Table 2.2. Limits of Detection (LoD) of given radioisotopes by Evolution 2 gamma-photondetection system- for finds on the surface and at 10 cm below the surface.............................9Table 2.3. Beach find rates 2006-2010 (particles and stones)...............................................11Table 2.4. Numbers of Particles and Stones recovered 2006-2010.......................................11Table 2.5. Numbers of alpha-rich, beta-rich and 60 Co rich Particles recovered 2006-2010 ...12Table 2.6. Analyses carried out on particles since 2006 by NPL ...........................................13Table 3.1. Total hectares monitored for each beach during the 2010/11 monitoringprogramme. ............................................................................................................................19Table 3.2. Total particle and stone beach finds during the 2010/11 monitoring programme. 19Table 3.3. Beach find rates (finds per hectare) throughout the history of the monitoringprogramme. ............................................................................................................................24Table 3.4. Changes in find classification since 2006..............................................................27Table 3.5. Find classification showing the types of beach finds recovered on beachessurrounding Sellafield.............................................................................................................28Table 3.6. Find numbers and activities by category and monitoring technique......................35Table 3.7. Alpha-rich sub-group numbers ..............................................................................40Table 3.8. Basic statistics for actinide activities based on log normally distributed data........47Table 3.9. Basic statistics data in 3.8 converted from the natural log values back to activities................................................................................................................................................48Table 3.10. Beta-rich Caesium Isotope Decay Factors..........................................................49Table 3.11. Beta-rich Find Estimates. ....................................................................................49Table 3.12. Basic statistics for 137 Cs activities based on log normally distributed data..........52Table 3.13. Basic statistics data in Table 3.12 converted from the natural log values back toactivities..................................................................................................................................52Table 3.14. f 1 factors derived by HPA in-vivo intestinal absorption study. .............................56Table 3.15. Overlap find numbers summary for Sellafield beach monitoring in 2010/11. ......58Table 3.16. Before Overlap Survey Analysis for Finds within Equipment LOD Range. .........58Table 3.17. Statistical techniques report recommendations...................................................59Table 3.18. Statistical sampling report recommendations......................................................62Table 7.1. Repeat areas for the 2011/12 beach monitoring programme................................96Table 7.2. Recommendations from BPM assessment. ........................................................105List of FiguresFigure 2.1. Location of the main beach areas in the vicinity of Sellafield.................................8Figure 3.1. NUVIA’s Beach monitoring Softrak vehicle ..........................................................18Figure 3.2. 2010/11 Monitoring extent from Drigg Point to St Bees .......................................20Figure 3.3. 2010/11 Monitoring extent from Whitehaven Harbour to Harrington....................21Figure 3.4. The distribution of particle and stone beach finds throughout the 2010/11monitoring programme. ..........................................................................................................22Figure 3.5. The distribution of particle and stone beach finds on Braystones and Sellafieldbeach throughout the 2010/11 monitoring programme. .........................................................25Figure 3.6. Changes in year on year find rate at beaches closest to Sellafield......................26Figure 3.7. Changes in find classification since 2006. ...........................................................27Figure 3.8. Geographic location of recovered alpha-rich and beta-rich throughout the 2010/11programme (excluding Whitehaven, Parton, Harrington and Allonby). ..................................29Figure 3.9. Location of recovered alpha-rich and beta-rich finds at Sellafield and Braystonesin 2010/11...............................................................................................................................30Figure 3.10. Location of recovered alpha-rich and beta-rich finds at St Bees in 2010/11......31© Nuclear Decommissioning Authority 2011. 4

SSEM/2011/4730 June 2011Figure 3.11. Diagram Representing Find Population number ................................................38Figure 3.12. Radiological Classification in the Find Population..............................................38Figure 3.13. Histogram of Log Normally Transposed Alpha Rich Particle 241 Am Activities forseparate Evolution 2 and Synergy Monitoring Periods. .........................................................40Figure 3.14. Alpha-rich Find Subgroups Based on their Actinide Activity Ratios ...................41Figure 3.15. Alpha-rich Find Subgroups without Error Bars...................................................42Figure 3.16. Separate Evolution 2 and Synergy 241 Am Activity Histogram.............................43Figure 3.17. Combined Evolution 2 and Synergy 241 Am Activity Histogram...........................43Figure 3.18. 239 Pu Activity Histogram. ....................................................................................44Figure 3.19. 238 Pu Activity Histogram. ....................................................................................44Figure 3.20. Probability Plot of Log of 241 Am Particle Activity (no LOD values in data set)....45Figure 3.21. Probability Plot of Log of 239 Pu Particle Activity (positive data only). .................45Figure 3.22. Probability Plot of Log of 238 Pu Particle Activity (positive data only). .................46Figure 3.23. Probability Plot of Log of 241 Am Activity for Particles found at the Sand Surface................................................................................................................................................47Figure 3.24. 137Cs Stone Activity Histogram.........................................................................50Figure 3.25. 137 Cs Particle Activity Histogram. .......................................................................50Figure 3.26. Probability plot of Log of 137 Cs Stone Activity.....................................................51Figure 3.27. Probability plot of Log of 137 Cs Particle Activity. .................................................51Figure 3.28. SEM Image of part A of beta-rich particle IM090340. ........................................54Figure 3.29. Possible structures for alpha-rich particles. .......................................................55Figure 3.30. Alpha-rich Particle Find Distances from the Sellafield pipeline. .........................57Figure 3.31. Find Overlap Outcomes. ....................................................................................58Figure 3.32. Swath bathymetry along in the Cumbrian coastline within the Fledermaus 3Dvisualisation software. The position of the pipe (black line) and the navigation buoys (redcubes) are shown. ..................................................................................................................66Figure 3.33. Plessey M021 current meter. Source: NOAA (National Oceanic andAtmospheric Administration) Photo Library and the Oceanographic Museum of Monaco.Photographer: Y. Berard. .......................................................................................................68Figure 3.34. Aquadopp and landing frame being deployed from the Sellafield Ltd vessel,Eagle. .....................................................................................................................................69Figure 4.1. Information leaflet produced by SL to advise local residents and visitors on thebeach monitoring programme. ...............................................................................................77Figure 7.1. 2011/12 Beach Monitoring Programme ...............................................................99Figure 7.2. St Bees beach repeat area for 2011/12. ............................................................100Figure 7.3. Braystones beach repeat areas for 2011/12. .....................................................101Figure 7.4. Sellafield beach repeat areas for 2011/12. ........................................................102Figure 7.5. Seascale beach repeat area for 2011/12 ...........................................................103Figure 7.6. Target area for the grab sampling work showing the position of the sea pipelinesand the location of the Aquadopp current profiler deployed to the north of the diffusers fromJune 2010 to February 2011 ................................................................................................109Figure 7.7. Draft Task Sheet for work to progress offshore monitoring................................111Figure 8.1. Programme of works ..........................................................................................115© Nuclear Decommissioning Authority 2011. 5

SSEM/2011/4730 June 20111. IntroductionAs part of Sellafield Ltd’s environmental monitoring programme, several streams of workhave been undertaken to understand the nature of radioactive particles that have beendetected on local beaches and to quantify the health risk they pose. This report provides thebackground to these work streams, details the progress that has been made in 2010/11 andsets out the intended programme of work for 2011/12 and beyond. In previous yearsseparate reports were produced for the beach monitoring and offshore monitoringprogrammes; both streams of work are covered in this report.Section 2 provides broad background to the work. It explains why particles are beingmonitored in the environment, what work has been undertaken to date and how the level ofrisk has been assessed.Section 3 provides detailed information on progress made in 2010/11 for the beachmonitoring and offshore monitoring programmes and work undertaken to support theassessment of risk. Physical and chemical analysis of items recovered from the beaches,investigations into the likely source(s) and pathway(s) of the finds, statistical techniques forinterpreting the data generated from beach monitoring, as well as research and developmentactivities are considered.Section 4 explains how the regulators and stakeholders have been engaged by Sellafield Ltdin the work streams so far and the framework for future interactions.Section 5 summarises the work done to assess the health risk posed by beach finds, whichhas been led by the HPA, how Sellafield Ltd are responding to the HPA’s recommendations,and outlines how this assessment will be updated as new data becomes available.Section 6 discusses the progress made against the original aims and objectives of the workstreams and how these have been developed, based on results and stakeholder input, into arevised set of objectives.Section 7 outlines the programme of work for 2011/12, arranged under the key objectives.Specifically, this covers the beach monitoring programme, offshore characterisation ofparticles, analysis of beach finds, statistical interpretation of data, managementarrangements and a summary of the estimated costs for the 2011/12 financial year. Howeach work stream represents BAT (Best Available Technique) is also considered.Section 8 outlines the programme of works to meet the key objectives.© Nuclear Decommissioning Authority 2011. 6

SSEM/2011/4730 June 20112. Background2.1 Origin of the large area beach monitoring programmeSellafield Ltd has been monitoring beaches on a limited scale since 1983 following beachcontamination caused by an abnormal effluent discharge. Surveys using hand-held detectorshad been focused on the most recent tide and debris line near the top of the beach (referredto as the “strandline”).In 2003, the routine strandline monitoring detected a particle of comparatively high activity,exhibiting approximately 3000 cps, high contact dose rates and a significant amount of 90 Sr(a beta-emitting radioisotope produced during nuclear fission), approximately 700 m north ofthe Sea pipelines. This was the first beach find since 1993.Triggered by the 2003 particle, the Environment Agency asked SL to trial more sensitivevehicle-mounted detection equipment, capable of monitoring large areas of beach. Modellingwork by Westlakes Scientific Consulting (WSC) predicted that any particles released from theend of the sea pipelines, the most obvious potential pathway by which particles fromSellafield could enter the environment, would be deposited on beaches between Sellafieldand Braystones and as a result of local sea currents (Vives Lynch, 2006) Therefore, in2006/7, a trial was conducted on beaches near Sellafield and Braystones (total of 14.4 ha).The trial detected populations of radioactive particles and led SL to establish an annual largearea beach monitoring programme to include monitoring of the seabed. Beaches weredefined using their commonly used names and natural breaks in the area of sand or shingle.A map showing the beaches referred to throughout this report is presented in Figure 2.1. The2007/8 beach programme monitored 150 ha of beaches from Parton to Drigg Point, withhand-held monitoring used where the terrain was inaccessible to the Hillcat vehicle. A limitedamount of monitoring was also completed further north at Goat Well Bay and SouthernessPoint in the Solway Firth to bound the spatial extent of beach finds and address the concernsof the Scottish Environmental Protection Agency (SEPA) that the Scottish coastline was notaffected.In subsequent years the beach survey areas were agreed in advance with the EA and writteninto the Compilation of EA Requirements (CEAR). In 2008/9 the total area was increased to250 ha, to reflect the large number of finds recovered and the maximum area that might berealistically surveyed with full-time deployment of one monitoring vehicle. In 2009/10, again250 ha was initially agreed with the EA. An additional 15 ha was added to providereassurance at two beaches with higher public occupancy- St Bees and Silecroft. For2010/11 a further 250 ha programme was agreed with the EA.The areas specified by the CEAR refer to the total new area covered during each visit toeach beach (e.g. 2 week period), such that any overlap in area within each visit is notcounted. In practice significant areas of beach are resurveyed within each visit but on asubsequent tide cycle (e.g. after the tide has come in and gone back out). Table 2.1 below,shows the total areas covered without overlap included since the start of the programme.© Nuclear Decommissioning Authority 2011. 7

SSEM/2011/4730 June 2011Figure 2.1. Location of the main beach areas in the vicinity of Sellafield.© Nuclear Decommissioning Authority 2011. 8

SSEM/2011/4730 June 2011Table 2.1. Beach area specified in the CEAR and monitored each yearFinancial CEAR Actual area coveredYear (ha)(ha)*Beaches surveyed2006/7 N/A 14.4 Braystones, Sellafield2007/8 150 205 Goat Well Bay, Southerness Point, Parton,Whitehaven, St Bees, Braystones,Sellafield, Seascale, Drigg2008/9 250 353 Allonby, Workington, St Bees, Braystones,Sellafield, Seascale, Drigg2009/10 265 354 St Bees, Nethertown, Braystones,Sellafield, Seascale, Drigg, Silecroft2010/11 250 319 St Bees, Braystones, Sellafield, Seascale,Drigg2011/12 150 N/A Allonby, Harrington, Parton, Whitehaven,St Bees, Nethertown, Braystones,Sellafield, Seascale, Drigg*With at least a tide between overlapping areas.2.2 Beach monitoring methodsSpecialist equipment, developed by Nuvia initially to meet the requirements of Dounreay, isused for the large area beach monitoring. An array of detectors is carried by a vehiclecapable of driving on the beach. Originally this was an eight wheeled vehicle (Hillcat) but thiswas replaced in 2009 with the Softrak vehicle which allows for a heavier load of detectors,more specifically addressing the situation at Sellafield.The NUVIA system was very efficient at detecting radionuclides thatemit medium to high energy gammas (e.g. 137 Cs, 60 Co etc.) over find depths in sand down to50 cm. It was also demonstrated to be effective for lower energy gammas (e.g. from 241 Am)but with some limitations on detection depth. With the turnover of sand due to tidal action andthe repeat monitoring of the sensitive areas this detection system was judged to be capableof providing data that can be used to give a realistic assessment of the population of gammaemitting particles. Using this system, particles containing either pure beta emitters or mainlyalpha emitters could only be detected if they emitted sufficient gamma radiation.The detection capability of Evolution 2 is given in Table 2.2. More details of the monitoringequipment used can be found in Nuvia’s 2010/11 Annual Report (Hall, 2010).Table 2.2. Limits of Detection (LoD) of given radioisotopes by Evolution 2 gamma-photondetection system- for finds on the surface and at 10 cm below the surfaceLimit of Detection137 Cs (Bq)60 Co (Bq)90 Sr/Y (Bq)241 Am (Bq)95% Confidence Typical Worst Typical Worst Typical Worst Typical WorstIntervalcase case case case case case case caseOn surface 9.00E+03 1.5E+04 4.00E+03 9.00E+03 1.50E+05 2.50E+05 4.00E+04 8.00E+04At 50 cm 4.00E+04 5.50E+04 1.50E+04 2.50E+04 5.50E+05 9.50E+05 4.00E+06 9.00E+06© Nuclear Decommissioning Authority 2011. 9

SSEM/2011/4730 June 2011In August 2009, the detection system was introduced. This systemincluded the original setup plus 8 FIDLER (Field Instrument for theDetection of Low-Energy Radiation) detectors. This enabled improved detection of pure betaemitters, such as 90 Sr/Y and low energy gamma emitting alpha-rich particles, such as 241 Am.A detailed field calibration of the both systems (Evolution 2 and Synergy) took place on Driggbeach in October 2009 (Beddow 2010a, b). For the Synergy system it was found that a 100kBq 137 Cs particle could reliably be detected to a depth of 200 mm and a 100 kBq 60 Coparticle to a depth of 300 mm. A 1000 kBq 137 Cs particle could reliably be detected to a depthof 400 mm and a 1000 kBq 60 Co particle could be detected to a depth of 400 mm. The mainconclusions were that the Synergy system could provide reliable detection for:10 kBq 137 Cs and 60 Co surface particles.10 kBq 60 Co particles to a depth of 100 mm.100 kBq 241 Am surface particles.1000 kBq 241 Am to 50 mm depth.1000 kBq 90 Sr/Y surface particles2.3 Beach monitoring findings to date2.3.1 LocationsSince the programme started in 2006, Sellafield beach has consistently been the area ofhighest numbers of finds, followed by Braystones beach. The distribution of finds is heavilyskewed to beach areas north of the Sellafield sea discharge pipeline, as expected from thenortherly sea currents. Approximately 50% of the finds were located within the first 0.5kilometre north of the Sellafield pipeline. Find numbers decline sharply south of Seascale,and north of St Bees Head. The distribution is generally similar for alpha-rich and beta richparticles (see definitions below).The most northerly particle find was at Allonby, and the most southerly at the south end ofDrigg beach. No particles have been found further north and south of these locationsrespectively, during the monitoring that has been carried out beyond these locations.A limited amount of monitoring has been carried out on beach areas at Nethertown andCoulderton (between Braystones and St Bees); the rocky nature of the beaches means thatthe monitoring vehicle is unable to access these areas.2.3.2 Find ratesTo examine any potential changes in the number of beach finds recovered, it is important toconsider the total area monitored in order to calculate a find rate, i.e. finds per hectare.A comparison of finds recovered since 2006/7 shows that the total find rate has varied overtime (Table 2.3). Find rates at St Bees, Seascale and Drigg have decreased year on yearsuggesting that finds are being recovered quicker than they are being replaced. AtBraystones, find rates had decreased until 2009/10 when they were the highest since2006/7. At Sellafield, find rates peaked in 2007/8, decreased in 2008/9 before rising to asimilar level to that in 2006/7 in 2009/10.However, care is needed when interpreting these rates because the number of visits to eachbeach within a given year, and therefore the interval between visits is not consistent. It is alsoto be expected that fresh areas of beach can be created or exposed after storm events, so© Nuclear Decommissioning Authority 2011. 10

SSEM/2011/4730 June 2011the time of the visit may be important. Furthermore, in August 2009, the Evolution 2 detectionsystem was replaced with the Synergy system with its better capability for detecting itemscontaining either pure beta emitters or mainly alpha emitters by their low energy gammaemission.Table 2.3. Beach find rates 2006-2010 (particles and stones)MonitoringFind rate (finds per hectare)area 2006/07 2007/08 2008/09 2009/10St Bees – 0.214 0.077 0.059Braystones 0.334 0.158 0.115 1.043Sellafield 1.671 4.003 1.747 2.181Seascale – 0.209 0.188 0.176Drigg – 0.254 0.051 0.000All 0.835 1.725 0.692 0.6812.3.3 Find sizesItems recovered from the beach range in size, from tens of microns to large stones. Prior tothe 2008/9 programme, any finds recovered from the beaches surrounding Sellafield weredescribed as either stones, particles or pebbles (i.e. rounded stones). Deciding whether afind was a pebble or a stone was open to interpretation so from the 2008/9 monitoringprogramme the pebble classification was removed. At the same time, the standard sedimentclassification system was applied to the beach finds; anything less than 2 mm in diameter(upper limit for sand grains) was classed as a particle and anything larger than or equal to 2mm as a stone. This classification allows a foundation on which to judge the potential for a“particle” to be ingested, inhaled or adhere to the skin. However, this is based on a visualassessment following coarse separation and there will always be some ambiguity for findsaround 2 mm in size unless they are sent for detailed analysis.Contaminated stones have mainly been found within a few hundred metres north of theSellafield pipeline. The furthest a stone has been recovered from the pipeline isapproximately 2.5 km at the northern end of Sellafield beach. Two stones have been foundon Seascale beach, the furthest south being approximately 2.5 km south of the pipeline.Table 2.4. Numbers of Particles and Stones recovered 2006-2010MonitoringareaNumber of finds2006/07 2007/08 2008/09 2009/10Particles Stones Particles Stones Particles Stones Particles StonesSt Bees – – 6 0 3 0 4 0Braystones 3 0 2 0 4 0 68 0Sellafield 4 5 129 204 79 141 102 50Seascale – – 7 0 10 3 17 0Drigg – – 5 0 2 0 0 0Allonby – – – – 1 0 – –Workington – – – – 1 0 – –All 7 5 149 204 100 144 191 50© Nuclear Decommissioning Authority 2011. 11

SSEM/2011/4730 June 20112.3.4 Find classificationAll finds are recovered and returned to Sellafield site for analysis in the laboratory usinggamma spectrometry. This measures the key radionuclides that are detected by theEvolution/Synergy system ( 137 Cs and 241 Am) and any other significant radionuclides (e.g.60 Co, 106 Ru). Finds with positive analytical results are broadly classified into alpha- or betarich:Finds with 241 Am activity greater than 137 Cs activity are classified as “alpha-rich”;Finds with 137 Cs activity greater than 241 Am activity are classified as “beta-rich”.Following the introduction of the Synergy monitoring system during the 2009/10 monitoringprogramme, which is more effective at detecting low energy alpha and pure beta emittersthan Evolution 2, the number of “alpha-rich” finds being recovered, particularly from Sellafieldand Braystones beaches, increased.A comparison of finds detected by the Synergy system (NaI detectors plus FIDLER probes)and those that would have detected using the Evolution 2 system (i.e. NaI detectors only)revealed that there would have been 55 fewer beach finds during 2009/10 if Synergy had notbeen introduced in August 2009 (D’Souza, 2010). The vast majority of the extra 55 findswhich Synergy detected were characterised as alpha-rich, reflecting the capability of Synergyto detect lower energy finds. Interpretation of this improvement is complicated because theSynergy system also introduced a carbon fibre detection box which also appears to havemade the NaI detectors more efficient.The number of beta-rich finds recovered has decreased from 322 in 2007/8, to 220 in 2008/9and 94 in 2009/10 despite the same total area being monitored (approximately 250 ha). Thecontinued reduction in 2009/10 is even more significant because of the use of more sensitivedetection equipment (Synergy). In addition to the alpha and beta rich find classification, a total of 12 finds have beenallocated a 60 Co rich classification since 2006. A 60 Co rich find is defined as a particle orstone where the 60 Co activity is positive and greater than the 137 Cs activity (but notnecessarily greater than 241 Am).Generally, 60 Co activity in the nuclear industry is associated with neutron activation of steelcomponents of the reactor fuel or its support structure. Superficially, this might appear tooffer an easier route for identifying the time and source of the release into the environment.In reality, however, the complexity of fuel handling and reprocessing operations together withsubsequent effluent treatment makes a definitive assessment very difficult.Table 2.5. Numbers of alpha-rich, beta-rich and 60 Co rich Particles recovered 2006-2010ClassificationNumber of Particles2006/07 2007/08 2008/09 2009/10Alpha-rich 1 31 24 140Beta-rich 6 117 74 4660 Co rich 0 5 2 5© Nuclear Decommissioning Authority 2011. 12

SSEM/2011/4730 June 20112.3.5 Analysis of findsFollowing the initial analysis of the finds at the Sellafield Ltd analytical laboratory, threeseparate batches of finds have been sent to the National Physical Laboratory (NPL) fordetailed analysis. NPL provide more in-depth information about their chemical/mineralcomposition, associated dose rates, isotopic composition, structure and potential bioavailabilityof the associated radioisotopes upon ingestion. Analysis methods have included:contact dose rates, gamma spectrometry, Scanning Electron Microscopy/Energy DispersiveX-Ray Spectroscopy (SEM/EDX), dissolution and leaching behaviour in seawater andsimulated human gut fluid. Separate studies were also conducted by HPA to determine thelikely uptake of activity in the human gut following ingestion. The uptake fraction of 238 Pu,239 Pu / 240 Pu and 241 Am for ten alpha rich particles measured in rats has been used by theHPA in their assessment of overall risk (Brown and Etherington, 2011).The analysis carried out from 2006 to date is summarised in Table 2.6. The results havebeen used by the HPA to demonstrate that the overall risk posed by both the alpha and betarichparticles is acceptable (see Section 5 for a full explanation). The Plutonium andAmericium isotope analysis and physical and chemical properties have been used by the SLParticles Sources and Pathways Working Group (PSPWG) to determine a likely candidatesource process for the alpha-rich particles (see below).Table 2.6. Analyses carried out on particles since 2006 by NPLType of AnalysisParticle Numbers AnalysedAlpha rich Beta richGamma spectrometry* 154 293Instrument dose rates 20 60TLD dose rates 20 60Mass 27 59Volume 23 41Density 19 57Scanning Electron Microscopy 33 62Energy Dispersive X-Ray 33 62Dissolution 23 55Pu isotopes 23Sr-90 8 54Tc-99 8 19Metals 8*Includes several analyses originating from the same particle, e.g. initial characterisation,after a seawater leach, after simulated gut dissolution and total dissolution.2.4 Sources and Pathways of beach findsAn assessment of the source and pathway of alpha-rich finds was co-ordinated by specialistsfrom the Sellafield Ltd central Environmental Management team, utilising the operationalknowledge and experience of representatives from key production, legacy and wastemanagement facilities on the Sellafield site (e.g. Magnox, Thorp, liquid effluent treatmentplants etc.), through the formation of the Particle Source & Pathway Working Group in 2007.Alpha-rich finds which contained sufficient actinide isotope concentrations had their agesestimated based on the relative decay of 239 Pu and 241 Pu, burn-up and cooling assumptions© Nuclear Decommissioning Authority 2011. 13

SSEM/2011/4730 June 2011as well as the type of fuel reprocessed (isotope ratios for each find were compared with fuelinventory data corresponding to the Magnox and oxide fuels reprocessed at Sellafield since1964). Age estimates were then compared with the operational records to check that theburn-up assumption used was consistent with fuels reprocessed at that time. The ageingmethodology has been independently peer-reviewed by the National Nuclear Laboratory andfound to be “fit for purpose” (Groves and Little, 2010).This work has been very resource-intensive and it has taken many months to complete.Hence, the first report was only completed in the second half of 2010 (Hackney, 2010). Theconclusions were:Based on radiochemical, chemical and physical characterisation of beach finds andreview of historic site practices and processes, the source of alpha-rich findsanalysed up to March 2009) is reprocessing of Magnox and oxide fuels on theSellafield site between the late-1960s and early 1980s. Particles could have beenreleased prior to the late-1960s but the low burnups of fuels processed in this periodwould not have yielded sufficient actinide activities to enable their detection on thebeaches.There is no evidence to link the beach finds with current reprocessing operations (i.e.Magnox or Thorp). This is supported by results from a programme of on-site workinvestigating solids exclusion in the site’s operational liquid effluent systems. To date,the analysis of multiple liquid samples across the main effluent systems on site hasnot identified the presence of any discrete active particles.The alpha-rich particles are not fragments of fuel, but most likely combinations ofnaturally-occurring beach material (e.g. silt, sand) and alpha-rich ferric hydroxideflocs produced through neutralisation of aqueous raffinates. These solids weredischarged to the Irish Sea with little or no abatement, in accordance with theRadioactive Substances Act 1960 authorisation at that time. Particles may have beenreleased into the environment shortly after their production or during the removal ofthe old sea lines between the early 1990s and 2006.Determining the source of beta-rich particles is more difficult because age estimates using137 Cs: 134 Cs ratios are restricted because 137 Cs is at LOD in a large proportion of finds. It istherefore only possible to say that finds are older than a certain age. Identifying potentialsources is also difficult because the particles exhibit a wide range of physical appearancesand elemental compositions (from EDX). A sub-group of metallic beta rich particles has beenidentified by the analysis which may offer some potential for identification of source material.To that end the 2010/11 analysis programme included forensic work to try and improve thequality of the estimates of elemental metal compositions.The presence or absence of 90 Sr rich particles has been a key driver for the analysis workbecause the 2003 find was almost pure 90 Sr particle. The presence of 90 Sr/Y is alsosignificant because of the high dose they can cause. A further 20 beta rich, potential 90 Sr,particles were analysed for 90 Sr in 2009/10. The combined results available from both the SLlaboratory and the Serco/NPL contract gave a maximum 90 Sr activity of 5E+04 Bq with anaverage activity of 3E+03 Bq, for those with positive results. The 90 Sr to 137 Cs ratio ranged for0.04 to 0.91, with approximately half of the finds having a 90 Sr activity greater than 10% ofthe 137 Cs activity. Although only 51 90 Sr analysis results are available, the 47 values abovethe limit of detection would suggest that the non-destructive testing results are sufficient tojudge the 90 Sr potential. As a further 17 beta-rich finds are current undergoing destructivetesting a decision on the need for further destructive testing will be made when their resultsare available (i.e. expected in September 2011).© Nuclear Decommissioning Authority 2011. 14

SSEM/2011/4730 June 20112.5 Offshore monitoringIn 2008 the EA specified that, .Subsequently, in April 2009 the EA revised the offshore requirement and specified thefollowing:Sellafield Ltd has been working on developing a risk-based approach to the work, withsignificant input from relevant Agencies (Food Standards Agency, Health Protection Agencyand Environment Agency) through the establishment of the Sellafield Sea-bed MonitoringWorking Group in 2009.Particle transport and dispersion modelling for the Sellafield marine environment was carriedout by CEFAS in 2009. It was agreed in February 2010 by the Working Group that the modelrequired further development and data to validate it (e.g. sediment mixing depth) before itcould be confidently used to inform seabed monitoring.SL have collected more information from the offshore environment (bathymetry data obtainedfrom LLWR, measurements of current profiles and wave parameters), so that a higherresolution particle transport and dispersion model can be developed. Research has alsotaken place into Woodhead drifters and particle tracer releases to help understand themovement of particles in the sea. Parallel to this, a range of seabed monitoring and samplingtechniques are being investigated (e.g. ROV, dredging, grab sampling, coring etc). Moredetails are provided in Section 3.3.Dounreay Site Restoration Ltd (DSRL) is continuing to deploy Remotely Operated Vehicletechnology to deliver their requirements to monitor and retrieve radioactive particles (mainly137 Cs) at Dounreay. Sellafield Ltd has continued to liaise with DSRL to discuss progress.Currently, the ROV is not deemed suitable for use at Sellafield because of its capability todetect alpha-rich material has not been proven.2.6 Risk AssessmentThe main aim of the beach monitoring programme has always been to establish andminimise health risks to the public where practicable. Since the start of large area beachmonitoring in 2006 Sellafield Ltd has provided the EA and the HPA with all the availablemonitoring and analysis data it has acquired to enable risks to be assessed. In 2007 the HPAgave their first formal advice:© Nuclear Decommissioning Authority 2011. 15

SSEM/2011/4730 June 2011The monitoring and analysis data were reviewed at joint regulator workshops on 28 June2007 and 25 November 2008. These workshops concluded that the alpha rich particles aremost significant regarding assessment of risks to members of the public. Prior to the start ofthe 2009/10 monitoring programme, the HPA had reviewed all the available data and advisedthat their original advice remained valid.In May 2008, the EA asked HPA to undertake a detailed assessment of the health risks topeople using the beaches along the Cumbrian coast from contaminated objects on thebeaches. The resulting report has recently been published (April 2011). The assessmentaddressed the likelihood that people using the beaches for various activities could come intocontact with a radioactive object and, in the unlikely event that an individual does come intocontact with such an object, what the resulting radiation doses and associated health riskswould be.The report concluded that the overall health risks for beach users are very low, andsignificantly lower than other risks that people accept when using the beaches (such asdrowning) and reaffirmed the original advice given in 2007 that, “no special precautionaryactions are required at this time to limit access to or use of the beaches”.In a letter from HPA to EA in April 2011 it was stated that, “”More details about the assessment of risk (dose) to members of the public and how risk willcontinue to be assessed as new data becomes available are presented in Section 5.© Nuclear Decommissioning Authority 2011. 16

SSEM/2011/4730 June 20113. Progress during 2010/113.1 Beach Monitoring 2010/11This section presents the results of the Sellafield beach monitoring programme in 2010/11. Inprevious years a separate report has been produced for beach monitoring. These areavailable on the EHS&Q Environment pages at www.sellafieldsites.com.3.1.1 IntroductionThe report is limited to the large area beach monitoring that was first introduced in 2006. Themonitoring is carried out by NUVIA Ltd on behalf of Sellafield Ltd (SL). The report does notcover the strandline monitoring that has been carried out routinely by SL since 1984(reported regularly to Environment Agency (EA) along with the rest of the Sellafield statutoryenvironmental monitoring programme). This report presents information on the number offinds, their frequency per hectare and their distribution on beaches surrounding Sellafield. Itpresents the latest conclusions on the likely sources of finds and the risks they pose to thegeneral public.3.1.2 Beach monitoring programme specification for 2010/11The current beach monitoring objectives are as follows;1. Determination of the risks to members of the public.2. Identification of the source(s) of the particles.3. Determination of a long term monitoring programme that represents Best PracticableMeans (BPM).4. Retrieve particles to allow comprehensive analytical screening to inform on thehazard from particles in the environment.5. To understand the full range of activity of particles in the environment.6. To understand the distribution of particles in the environment (including seabed).7. To reassure beach users that monitoring has been undertaken and particles havebeen promptly detected and removed.To meet these objectives, the Environment Agency (EA) has placed a statutory monitoringrequirement on SL to deliver a large scale beach monitoring programme. This is part of anagreed programme of works specified in the current Compilation of Environment AgencyRequirements (Paragraph 21 from CEAR 1/19/09 Issue 1 (010411)):3.1.3. Achievement of the 2010/11 beach monitoring programmeThe Groundhog TM Synergy detection system was used throughout the duration of the2010/11 beach monitoring programme. The Groundhog TM Synergy system includes theoriginal Groundhog TM Evolution 2 setup (used in previous years of monitoring) plus 8 FIDLER© Nuclear Decommissioning Authority 2011. 17

SSEM/2011/4730 June 2011(Field Instrument for the Detection of Low-Energy Radiation) detectors mounted on the frontof the Softrak monitoring vehicle, Figure 3.1. Since it was introduced in August 2009, thesophisticated array of probes has resulted in superior detection of alpha and beta-richradioactive particles.For more details regarding radiological detection and monitoring equipment, visit the EHS&Qenvironment pages at www.sellafieldsites.com.Figure 3.1. NUVIA’s Beach monitoring Softrak vehicleThe monitoring programme area has increased considerably since its inception in 2006. Thetotal monitoring area achieved for the 2010/11 programme was 319 hectares (Table 3.1,Figure 3.2, Figure 3.3). For 2010/11, the CEAR requirement stated a minimum survey areaof 250 hectares of beach. In the last monitoring year, over 25 hectares of beach wassurveyed beyond the typical monitoring extent (St Bees Head to Drigg Point). Beach surveyswere conducted on Whitehaven Harbour, Whitehaven North, Parton, Harrington and Allonbybeach as part of the investigation periods. The Softrak monitoring vehicle was unable toaccess Whitehaven Harbour or Parton beach so a single hand-held Sodium Iodide detectorwas used as an alternative. The detector is mounted in a lightweight case and suspendedbetween two operators whilst monitoring the survey area. The hand held system uses thesame detection criteria as the vehicle based Evolution 2 array.Table 3.1 summarises the monitoring locations and hectare coverage as part of the 2010/11programme. Hectare totals reflect the daily monitoring areas with at least one tide betweeneach period (i.e. typical sand turnover between tides is 10 centimetres and hence presents anew monitoring area). This gives a higher total than the area used for compliance with theauthorisation requirements, which is calculated based on the total monitoring area in a beach© Nuclear Decommissioning Authority 2011. 18

SSEM/2011/4730 June 2011visit. The difference due to overlap between days can be significant, especially if accessroutes to various parts of the beach are limited. The percentages in Table 3.1 below havebeen calculated using the total area within the designated box on a map and the realisticarea that is available after tide, rocks and access factors have been taken into account.Table 3.1. Total hectares monitored for each beach during the 2010/11 monitoring programme.Monitoringarea3.1.4 Beach FindsNumber of daysArea covered(ha)Available area(ha)% of monitoringareaAllonby 4 10.44 136.90 8%Harrington 6 3.90 12.24 32%Parton 8 4.14 3.53 117%Whitehaven 10 7.19 3.86 186%St Bees 37 53.07 28.50 186%Nethertown 7 3.67*Difficult toassessN/ABraystones 57 76.59 18.90 405%Sellafield 49 67.13 54.10 124%Seascale 32 51.06 80.70 63%Drigg 20 41.81 196.70 21%* Nethertown is a very rocky beach with lots of boulder so sand coverage is difficult to calculate.During the 2010/11 monitoring programme, a total of 383 finds were recovered from thebeaches surrounding the Sellafield Nuclear Licensed Site (Table 3.2, Figure 3.4). Of these,348 were classified as particles and the remaining 35 were classified as stones.Table 3.2. Total particle and stone beach finds during the 2010/11 monitoring programme.MonitoringareaParticles recoveredin 2010/11Stones recoveredin 2010/11Total in2010/11Allonby 0 0 0Harrington 2 0 2Parton 0 0 0Whitehaven 9 0 9St Bees 60 0 60Nethertown 0 0 0Braystones 115 0 115Sellafield 142 35 177Seascale 10 0 10Drigg 10 0 10Total 348 35 383© Nuclear Decommissioning Authority 2011. 19

SSEM/2011/4730 June 2011Figure 3.2. 2010/11 Monitoring extent from Drigg Point to St Bees© Nuclear Decommissioning Authority 2011. 20

SSEM/2011/4730 June 2011Figure 3.3. 2010/11 Monitoring extent from Whitehaven Harbour to Harrington© Nuclear Decommissioning Authority 2011. 21

SSEM/2011/4730 June 2011Figure 3.4. The distribution of particle and stone beach finds throughout the 2010/11monitoring programme.© Nuclear Decommissioning Authority 2011. 22

SSEM/2011/4730 June 2011The total number of beach finds recovered in 2010/11 increased considerably compared tothe previous two years of monitoring (244 in 2008/09 and 241 in 2009/10). Following theintroduction of the Groundhog TM Synergy detection system in August 2009, the total find ratehas increased due to its enhanced detection capability. As Synergy was operationalthroughout the entire 2010/11 monitoring programme, this has resulted in a marked increasein the number of finds compared to the previous Groundhog TM Evolution 2 system. Theproportion of beach finds classified as stones (larger than 2 mm in diameter) decreasedsignificantly to just 9% in 2010/11. The reduction in the number of recovered stones isconsistent with the last two monitoring years. This supports the theory that the number ofcontaminated stones in the beach environment is decreasing.Over 76% of beach finds were recovered on Sellafield (46%) or Braystones (30%) beachduring 2010/11 which is where a significant proportion of the monitoring effort is focussed(144 hectares, 45%). This follows the trend previously reported for earlier monitoringprogrammes and is probably the result of a prevailing northerly current in the Irish Sea whichmay transport active particles and some small stones in this direction (Figure 3.5). Moreover,this distribution is also consistent with modelling work undertaken in 2006 (Vives Lynch,2006). As in previous years, contaminated stones are consistently recovered close to theNuclear Licensed Site. All but one stone was recovered within 1.25 km of the Sellafieldpipeline during 2010/11. The distribution of particle finds is more random reflecting greatermobility in the dynamic beach environment due to their size. There appears to be a higherdensity of finds at Braystones but this is misleading when only considering the number offinds and not the total survey area. When this is taken into consideration the number ofrecovered finds is considerably lower than on Sellafield beach (see section 3.1.5.3).A total of 60 finds were recovered at St Bees during the latest monitoring programme,considerably higher than previous monitoring years. This could be attributed to the dynamicnature of the beach environment which experiences significant changes in sand height,potentially exposing “new” finds. Alternatively, it could also be the result of Groundhog TMSynergy which is capable of detecting finds previously not visible with the Groundhog TMEvolution 2 system.Appendix 1 shows the distribution of the beach finds for the remaining beaches plus theextents which indicate the area monitored throughout the 2010/11 programme. Seascalebeach was covered extensively with approximately 60% coverage of the available area. Intotal, 10 particle finds were recovered and most of these were located in front of the car parkarea of the beach reflecting the area surveyed. During 2010/11, 10 particle finds were alsorecovered on Drigg beach. Five finds were recovered close to the northerly car park area andthe remaining five were recovered at the southern end of the beach at Drigg point. As part ofthe investigation period new monitoring areas were surveyed at Whitehaven north beach andWhitehaven Harbour as well as at Harrington. A total of nine finds were recovered atWhitehaven (eight on north beach and one within the harbour). Two finds were detected andrecovered at Harrington. Monitoring was conducted both within the harbour walls and on thesurrounding beach but both finds were recovered within the harbour. No finds wererecovered at Allonby, Parton or Nethertown despite monitoring over 18 hectares using eitherthe Softrak and/or hand-held instrumentation.To examine any potential changes in the number of beach finds recovered, it is important toalso consider the total area monitored in order to calculate a find rate. An assessment of the© Nuclear Decommissioning Authority 2011. 23

SSEM/2011/4730 June 2011number of finds recovered during 2010/11 shows that the total find rate has increasedcompared to the last two years monitoring but remains lower than the highest rate in 2007/08(Table 3.3). The increase in find rate correlates with the introduction of Synergy in August2009 as a result of enhanced detection capability. Interestingly, if Synergy had beenoperational throughout all of 2009/10 then the find rate would be similar to that of 2010/11.This suggests that Synergy is the reason for increased find rate rather than an increase inthe number of particles in the environment. Furthermore, there have been so significantstorm events which could have resulted in a drastic change in the distribution of particles inthe environment.Table 3.3. Beach find rates (finds per hectare) throughout the history of the monitoringprogramme.Monitoringarea2006/07 2007/08 2008/09 2009/10 2010/11Allonby – – 0.051 – 0Harrington – – – – 0.513Parton – – – – 0Whitehaven – – – – 1.251St Bees – 0.214 0.077 0.059 1.131Nethertown – – – 0 0Braystones 0.334 0.158 0.115 1.043 1.501Sellafield 1.671 4.003 1.747 2.181 2.637Seascale – 0.209 0.188 0.176 0.196Drigg – 0.254 0.051 0 0.239Silecroft – – – 0 –All 0.835 1.725 0.692 0.681 1.201‘–‘ indicates that no monitoring was carried out.Find rates were highest at Braystones and Sellafield which is consistent with previous yearsof monitoring (Figure 3.6). Beach finds were recovered at Whitehaven and Harrington as partof the investigation period and because a relatively small area was monitored, this hasresulted in a moderately high find rate. Further monitoring as part of the 2011/12 programmewill reveal whether the find rates in Table 3.3 are a true reflection of the number of particlesat Whitehaven and Harrington.© Nuclear Decommissioning Authority 2011. 24

SSEM/2011/4730 June 2011Figure 3.5. The distribution of particle and stone beach finds on Braystones and Sellafieldbeach throughout the 2010/11 monitoring programme.© Nuclear Decommissioning Authority 2011. 25

SSEM/2011/4730 June 20114.5004.000Find Rate (finds per ha)3.5003.0002.5002.0001.5001.0002006/072007/082008/092009/102010/110.5000.000St Bees Nethertown Braystones Sellafield Seascale DriggMonitoring AreaFigure 3.6. Changes in year on year find rate at beaches closest to SellafieldThe key radionuclides detected by the Groundhog TM Synergy monitoring are 137 Cs and241 Am. Consequently, initial characterisation of each find recovered via the monitoringprogramme concentrates on these isotopes, such that, for positive analytical results; Finds with 241 Am activity greater than 137 Cs activity are classified as “alpha-rich”Finds with 137 Cs activity greater than 241 Am activity are classified as “beta-rich”.Finds with positive 60 Co activity and greater than the 137 Cs activity are classified as“Cobalt-rich”When Synergy was introduced in 2009, its greater capability for detecting low energy alphaand pure beta emitters resulted in a significant change in the find profile. In the latter half ofthe 2009/10 programme the number of finds classified as “alpha-rich” increased notably andthis trend continued throughout the 2010/11 annual beach monitoring programme (Table3.4). Over 84% of all finds were classified as alpha-rich and were detected on most beachesthat were surveyed (Table 3.5, Figure 3.8). The majority of beta-rich and a significantproportion of alpha-rich finds were recovered at Sellafield and Braystones (Figure 3.9).The number of finds classified as beta-rich continued to decline (down 36% compared to2009/10) even with the large increase in the total number of finds recovered throughout theprogramme. This trend is consistent with previous monitoring reports and suggests that theactive particles/stones are being removed (by the monitoring/retrieval programme) fasterthan they are becoming available in the beach environment. Furthermore, over 80% of betarichfinds were recovered from Sellafield beach which is also consistent with previousmonitoring programmes.© Nuclear Decommissioning Authority 2011. 26

SSEM/2011/4730 June 2011Table 3.4. Changes in find classification since 2006.Classification 2006/07 2007/08 2008/09 2009/10 2010/11Alpha-rich 1 31 24 142 322Beta-rich 11 315 218 94 60Cobalt-rich 0 5 2 5 1All 12 351 244 241 383The large increase in find rate at St Bees (see 3.1.5.3) is likely to be the result of Synergy as57 finds, out of 60 recovered in 2010/11, were classified as alpha-rich (Figure 3.10). Findsdetected on other beaches such as Drigg, Whitehaven and Harrington have all beenclassified as alpha-rich except for one beta-rich find in Whitehaven Harbour (Table 3.5). Thelarge number of alpha-rich finds provides further evidence of the capability of Synergy fordetecting low energy radiation. A total of seven beta-rich finds and one Cobalt-60 rich findwere recovered from Braystones beach but the remaining 107 were classified as alpha-rich.No beta-rich finds were recovered from Drigg, Seascale or Harrington during 2010/11however beta-rich finds have been recovered on Drigg and Seascale beach in previousmonitoring years. This is further evidence that the “population” of beta-rich finds maybe beingremoved faster than they are becoming available in the beach environment.350300Total number of Finds250200150100Alpha-richBeta-richCobalt-rich5002006/07 2007/08 2008/09 2009/10 2010/11Monitoring YearFigure 3.7. Changes in find classification since 2006.© Nuclear Decommissioning Authority 2011. 27

SSEM/2011/4730 June 2011Table 3.5. Find classification showing the types of beach finds recovered on beachessurrounding Sellafield.MonitoringareaAlpha-rich Beta-rich Cobalt-richTotal in2010/11Allonby 0 0 0 0Harrington 2 0 0 2Parton 0 0 0 0Whitehaven 8 1 0 9St Bees 57 3 0 60Nethertown 0 0 0 0Braystones 107 7 1 115Sellafield 128 49 0 177Seascale 10 0 0 10Drigg 10 0 0 10Total 322 60 1 383In addition to the alpha and beta rich find classification, a total of 13 finds have beenallocated a 60 Co rich classification since the large area beach programme began in 2006.During 2010/11, only one 60 Co rich find was recovered from Braystones beach.Generally, 60 Co activity in the nuclear industry is associated with neutron activation of steelcomponents of the reactor fuel or its support structure. Superficially, this might appear tooffer an easier route for identifying the time and source of the release into the environment.In reality, however, the complexity of fuel handling and reprocessing operations together withsubsequent effluent treatment makes a definitive assessment very difficult. At Sellafield, a60 Co rich particle was found on Sellafield beach in 1988 close to the factory sewer outfall,which prompted an investigation into its potential source. Despite being able, from the tracemetals analysis, to identify which batch of fuel it was derived from, it was not possible todetermine how it came to be on the beach.© Nuclear Decommissioning Authority 2011. 28

SSEM/2011/4730 June 2011Figure 3.8. Geographic location of recovered alpha-rich and beta-rich throughout the 2010/11programme (excluding Whitehaven, Parton, Harrington and Allonby).© Nuclear Decommissioning Authority 2011. 29

SSEM/2011/4730 June 2011Figure 3.9. Location of recovered alpha-rich and beta-rich finds at Sellafield and Braystones in2010/11.© Nuclear Decommissioning Authority 2011. 30

SSEM/2011/4730 June 2011Figure 3.10. Location of recovered alpha-rich and beta-rich finds at St Bees in 2010/11.© Nuclear Decommissioning Authority 2011. 31

SSEM/2011/4730 June 20113.1.5 Risks from particles found in the environmentThe Health Protection Agency has continued to advise the Environment Agency on the risksassociated with using the beaches around Sellafield. Throughout the last six years SellafieldLtd has provided the EA and the HPA with all the available monitoring and analysis data ithas acquired to assist with determining the risk of particles in the environment.As part of formulating the overall risk, the Food Standards Agency (FSA) has also beenasked for their position regarding risks from consumption of seafood.In April 2011 the Health Protection Agency published their risk assessment (Brown andEtherington, 2011).Copied below is the assessment synopsis:The HPA confirm that the advice provided in 2009 (Cooper, 2009), that "no specialprecautionary actions are required at this time to limit access to or use of beaches" remainsvalid. The FSA have also confirmed that the risks associated with consumption of seafood"is acceptable" (Tossell, 2011).3.1.6 ConclusionsIn total, 319 hectares, between Allonby and Drigg point were monitored and 383 radioactivefinds were recovered. The overall number of finds and associated find rate has increasedcompared to the previous year of monitoring. However this is attributed to the introduction ofthe more sensitive Groundhog TM Synergy detection array.The overall distribution of finds corresponded with previous monitoring years, with a closegeographic association with the Sellafield Nuclear Licensed Site. Furthermore, a significantproportion of all beach finds were recovered on Sellafield and Braystones beach which isconsistent with modelling work undertaken in 2006 (Vives Lynch, 2006). Finds were detectedon new monitoring areas at Whitehaven and Harrington and further monitoring will be carriedout on these areas in 2011/12.© Nuclear Decommissioning Authority 2011. 32

SSEM/2011/4730 June 2011The number of finds classified as Beta-rich has continued to decrease (despite an overallincrease in the total number of finds) which suggests that this category of activeparticles/stones is being removed (by the monitoring/retrieval programme) faster than theyare becoming available in the beach environment.The introduction of Synergy enhanced the ability to detect lower energy gamma radiation,which includes 241 Amand consequently finds characterised as Alpha-rich. 2010/11 was thefirst year where the Synergy detection system was used for the entire annual programme.This resulted in a much higher find rate compared to the last two monitoring years. Withsufficient monitoring, the Alpha-rich find rate may also start to decrease (similar to the patternfor Beta-rich finds) as they are removed via the monitoring/retrieval programme.HPA have published its detailed risk assessment and have confirmed that the adviceprovided in 2009 remains valid (Cooper, 2009), they advise that:3.2 Find Analysis and Statistics3.2.1 IntroductionParticles and stones recovered from beaches as part of the monitoring/retrievals programmeare sent to the Sellafield Analytical Service for an initial estimate of the activity of gammaemitting radionuclides. A high resolution gamma scan technique is used on the 'as received'beach finds and activities for 60 Co, 106 Ru, 125 Sb, 134 Cs, 137 Cs and 241 Am radionuclides arereported. The analysis report includes these radionuclides, even if they are at the limit ofdetection, plus any other significant gammas detected. Alpha-rich finds with significant 241 Amactivity can undergo further assessment for Plutonium isotope activities. This data providesconfirmation of the find category, which is provisionally allocated using the monitoringdata.To allow further find characterisation, a series of external analysis contracts have beenplaced with Serco, starting in December 2007 and continuing to date. A total of 123 findshave been analysed via these contracts, with work on find tranche 1 and 2 complete and findtranche 3 ongoing. The finds selected for these contracts were judged to give arepresentative sample of those recovered at the time of contract placement. The analysesselected for the contracts focus on identifying public risk, origins of finds and determination ofthe best practicable means (BPM) methodology for beach monitoring. Serco employed theNational Physical Laboratory (NPL) to undertake the main analysis work and the HealthProtection Agency (HPA) to undertake intestinal absorptions studies, on a selection ofalpha-rich finds.The sequence of the analyses is carefully designed with hold points at critical stages (e.g.hold for SL and EA approval before starting on destructive analyses etc.). The analysessteps are as follows:i) Drying, separation and washing.ii)iii)Scaled colour photography.Estimated activity in 'as received' finds, 'separated' finds and residues using highresolution gamma spectroscopy calibrated to give limits of detection (LODs) for134 Cs in the range of 1E+00 Bq to 1E+03 Bq, for 237 U, 238 Pu and 239 Pu (in the© Nuclear Decommissioning Authority 2011. 33

SSEM/2011/4730 June 2011presence of 241 Am at 1E+04 Bq) in range of 1E+00 Bq to 1E+03 Bq. All otheradditional radionuclides detected above limit of detection are reported.iv) Measurement of beta gamma and gamma contact dose rates from separatedfinds using a Mini-Instruments SmartIon type ion chamber.v) Mass determination using Mettler AT balance capable of 2 microgram resolution.vi) Density determination by sequential fluid immersion in haloalkanes.vii) Shape determination using Alicona imaging.viii) Scanning electron microscopy imaging (SEM) (using non-coated technique andstub mounted on carbon mounting discs) on separated find and after bothstomach and gut leaching stages.ix) Energy dispersive X-ray analysis (EDX) on non-coated stub mounted separatedfind and after both stomach and gut leaching stages.x) Sequential leaching using simulated stomach solution, simulated gut solution, andtotal dissolution using mineral acids.xi) Solutions content determination of total beta, 60 Co, 90 Sr, 106 Ru, 125 Sn, 134 Cs, 137 Cs,152 Eu, 154 Eu, 155 Eu, 231 Th, 234 Th, 234 Pa, 238 Pu, 239 Pu, 240 Pu, 241 Pu, 242 Pu , 241 Am, 234 U,235 U, 236 U, and 238 U. Actinide analysis by alpha spectrometry and inductivelycoupled plasma mass spectrometry (ICP-MS), subcontracted to AMEC'sanalytical laboratory NIRAS. Metals analysis by inductively coupled plasmaoptical emission spectrometry (ICP-OES), subcontracted to the Scientific AnalysisLaboratory (SAL).xii) Solid content determination of total beta, 60 Co, 106 Ru, 125 Sn, 134 Cs, 137 Cs, 152 Eu,154 Eu, 155 Eu, 231 Th, 234 Th, 234 Pa, 238 Pu, 239 Pu, 240 Pu, 241 Pu, 242 Pu , 241 Am, 234 U, 235 U,236 U, and 238 U.The first Serco report was issued in December 2009 (Cowper ., 2009) and the second inJuly 2010 (Clacher ., 2010). The third report is due to be published in September 2011In October 2008 a Geographic Information System (GIS) was developed with Jacobs tohandle beach monitoring data and give a visual interpretation that could be more easilyunderstood. The data processed by this system, and its graphical outputs, have been usedthroughout this report. The GIS support contract has been renewed since the initial setting upof the GIS with the focus mainly on consolidating the facilities provided and expanding theiruse. GIS development is ongoing to add tools to help identify beach find repopulation, tocreate a web-based GIS for wider dissemination of information and to expand on thestatistical analysis of spatial factors.Work has continued in 2011/12 on the statistical interpretation of the data through a contractstarted in August 2010 with the Department of Environmental Statistics at GlasgowUniversity. Contract deliverables include advice of how best to analyse the existing beachmonitoring data using statistical techniques (Scott and Tyler, 2011a) and what beachmonitoring programme will maximises the potential for meaningful statistical analysis (Scottand Tyler, 2001b).3.2.2 What has been achieved with this analytical data?Finds are grouped into particles and stones using the geological classification of coarse sand(i.e. International diameter of 0.2 to 2 mm) and gravel/stones (i.e. International diameter of >2 mm). A particle is therefore defined as being less than or equal to 2 mm in diameter and astone as being greater than 2 mm in diameter. It is recognised that not all finds are sphericaland a visual inspection of the find is made during recovery. In most cases the particle orstone judgement is unambiguous with just 11% of stone finds with size estimates less than 3mm.© Nuclear Decommissioning Authority 2011. 34

SSEM/2011/4730 June 2011Particle and stone finds are further sub-divided initially into an alpha-rich or beta-richcategories during recovery using count rate and dose rate measurements. The alpharichand beta-rich find categories are expanded to include 60 Co-rich and excess beta-richcategories when the high resolution gamma scan results are available. The definitions forthese categories are as follows: Alpha-rich: Finds with positive 241 Am activity greater than 137 Cs activity. Beta rich: Finds with positive 137 Cs activity greater than 241 Am activity and NOT 60 Corich.60 Co-rich: Finds with positive 60 Co activity greater than 137 Cs activity.Excess beta-rich: Finds with a contact beta-gamma dose rate divided by the 137 Csactivity greater than 15 mSv/h per Bq 137 Cs AND NOT Alpha-rich AND NOT 60 Co-rich.Note that finds in this category are potential candidates for a high energy beta emittersuch as 90 Sr.An assessment of the 1233 finds found up to 31 st March 2011 shows that most alpha-richfinds have little beta radionuclide activity and most beta rich-finds have little actinide activity.Similarly, 60 Co-rich finds have mainly 60 Co activity and the excess beta-rich finds are alsomainly beta-rich. Exceptions to these general rules are rare (i.e. 3 unusual alpha-rich findsout of 514 alpha-rich finds in total; see below for other categories). Table 3.6 below gives asummary of the numbers of finds in each category and their average and maximum activities.The data is split between monitoring techniques with Groundhog TM Evolution 2 employedbetween November 2006 and August 2009 and Groundhog TM Synergy employed betweenAugust 2009 and the end of the reporting period (i.e. 31 st March 2011).Table 3.6. Find numbers and activities by category and monitoring techniqueAlpha-rich Activity summary 1 Evolution 2 SynergyTotal number 63 457No. of particles 60 454No. of stones 3 3Particle Mean 241 Am 7.69E+04 Bq 2.95E+04 BqParticle Max. 241 Am 6.34E+05 Bq 2.52E+05 BqParticle Min. 241 Am 3.23E+03 Bq 2.20E+03 BqStone Mean 241 Am 1.74E+04 Bq 2.40E+05 BqStone Max. 241 Am 3.54E+04 Bq 6.18E+05 BqStone Min. 241 Am 7.60E+03 Bq 5.13E+04 BqParticle Mean 137 Cs 2.50E+01 Bq 2.93E+01 BqParticle Max. 137 Cs 9.03E+01 Bq 6.23E+01 BqParticle Min. 137 Cs 1.18E+01 Bq 1.90E+01 BqStone Mean 137 Cs 4.70E+03 Bq 3.64E+01 BqStone Max. 137 Cs 7.20E+03 Bq 5.46E+01 BqStone Min. 137 Cs 1.80E+01 Bq 2.62E+01 Bq© Nuclear Decommissioning Authority 2011. 35

SSEM/2011/4730 June 2011Beta-rich Activity Summary 1 Evolution 2 SynergyTotal number 597 101No. of particles 225 45No. of stones 372 56Particle Mean 241 Am 2.07E+02 Bq 3.45E+02 BqParticle Max. 241 Am 1.15E+03 Bq 1.36E+03 BqParticle Min. 241 Am 8.31E+00 Bq 1.28E+02 BqStone Mean 241 Am 3.26E+02 Bq 5.50E+02 BqStone Max. 241 Am 4.99E+03 Bq 2.50E+03 BqStone Min. 241 Am 5.31E+01 Bq 1.98E+02 BqParticle Mean 137 Cs 1.64E+04 Bq 2.56E+04 BqParticle Max. 137 Cs 1.09E+05 Bq 2.92E+05 BqParticle Min. 137 Cs 4.75E+02 Bq 2.92E+03 BqStone Mean 137 Cs 4.00E+04 Bq 7.37E+04 BqStone Max. 137 Cs 8.75E+05 Bq 1.04E+06 BqStone Min. 137 Cs 1.93E+03 Bq 4.76E+03 Bq60 Co-rich Activity Summary 1 Evolution 2 SynergyTotal number 11 2No. of particles 10 2No. of stones 1 0Particle Mean 60 Co 1.27E+04 Bq 1.63E+04 BqParticle Max. 60 Co 1.97E+04 Bq 2.38E+04 BqParticle Min. 60 Co6.21E+03 BqStone Mean 60 Co 2.35E+04 Bq Not AvailableStone Max. 60 Co 2.35E+04 Bq Not AvailableStone Min. 60 Co 2.35E+04 Bq Not AvailableParticle Mean 137 Cs 1.04E+02 Bq 1.14E+02 BqParticle Max. 137 Cs 1.30E+02 Bq 1.45E+02 BqParticle Min. 137 Cs7.70E+01 BqStone Mean 137 Cs 1.44E+02 Bq Not AvailableStone Max. 137 Cs 1.44E+02 Bq Not AvailableStone Min. 137 Cs 1.44E+02 Bq Not Available© Nuclear Decommissioning Authority 2011. 36

SSEM/2011/4730 June 2011Excess Beta-rich Activity1Summary (all beta-rich)Evolution 2 SynergyTotal number 26 2No. of particles 25 2No. of stones 2 0 0Particle Mean 90 Sr 3 3.82E+03 Bq Not AvailableParticle Max. 90 Sr 3 1.47E+04 Bq Not AvailableParticle Min. 90 Sr 3 2.33E+02 Bq Not AvailableParticle Mean 137 Cs 8.33E+03 Bq 4.05E+03 BqParticle Max. 137 Cs 2.72E+04 Bq 4.39E+03 BqParticle Min. 137 Cs 3.08E+03 Bq 3.70E+03 BqParticle Mean 137 Cs/ 90 Sr ratio 4.4 Not AvailableParticle Max. 137 Cs/ 90 Sr ratio 23.2 Not AvailableParticle Max. 137 Cs/ 90 Sr ratio 0.6 Not Available1. Averages and minimum values include reported limit of detection values.2. One granite chip (most probably from the adjacent railway bed) was initially identified as excessbeta but was later categorised as naturally occurring material based on the 226 Ra activity.3. Evolution 2 finds based on 90 Sr and 137 Cs Serco analysis results from 25 particles categorised asexcess beta-rich.The above find categorisation provides a structure for reporting the key findings from theSellafield Ltd analysis, as follows:Using the size categories the population of particle and stone finds can be placed into tworeservoirs; the first being the area of beach down to low tide and the second being the areabelow the low tide line (generically called sub-sea). There is an interchange between thesereservoirs that depends on a complex combination of factors and is the subject of the subseainvestigation. A visual description of the whole population of finds, with their componentparts, is represented by areas in Figure 3.11 below. In this diagram the beach particles andstones areas and their corresponding sub-sea areas are roughly based on the finds found todate and an assumption that the interchange rates between beach and sub-sea for particlesand stones is the same. This is a starting point to help visualise the find populations andweaknesses with respect to a representative sampling programme and lack of knowledge ofthe beach to sub-sea interchange rates are being addressed.© Nuclear Decommissioning Authority 2011. 37

SSEM/2011/4730 June 2011Find Population438 stones recoveredfrom November 2006 to31/03/2011795 particles recoveredfrom November 2006to 31/03/2011Beach particlepopulationBeachStonespopulationSub-sea particlepopulationSub-seaStonespopulationFigure 3.11. Diagram Representing Find Population numberIn a similar way to the whole population, the beach particle population is represented inFigure 3.12 below. The areas are again an approximate representation of the relativepopulation sizes for the particle categories and are based on particles found to date. Theuncertainty in the relative population sizes will again depend on how representative thesampling programme is for the particle population.Beach Particle Population514 alpha-rich particlesrecovered fromNovember 2006 to31/03/2011Alpha-rich particlepopulation11 60 Co-rich particlesrecovered fromNovember 2006 to31/03/201160 Co-richparticlepopulation270 beta-rich particlesrecovered fromNovember 2006 to31/03/2011Beta-rich particlepopulationExcess beta-richpopulationFigure 3.12. Radiological Classification in the Find Population27 Excess beta-richparticles recovered fromNovember 2006 to31/03/2011© Nuclear Decommissioning Authority 2011. 38

SSEM/2011/4730 June 2011The problem associated with a statistically representative sampling programme is complexand can be intractable, as indicated in the statistical sampling report (Scott and Tyler,2011b). However, it should be noted that sampling over the last 4 and a half years hasdelivered a sampling programme whereby a significant proportion of the beach area hasbeen visited on multiple occasions. Furthermore, this increases the potential to detectparticles of all activities as they are turned over within the sand (i.e. unless the particles arefixed in a stratum they will visit the surface due to the churning affect of the tides). Whilstconsidering the best approach to future sampling programmes an assessment is needed ofthe relationship between the find populations and finds found to date. Four scenarios can bepostulated in this respect.a) The finds found to date are a small proportion of the whole population, whichinterchange freely with sub-sea populations and hence can be treated as a singlepopulation.b) The finds found to date are a significant proportion of the whole population, whichinterchange freely with sub-sea populations and hence can be treated as a singlepopulation.c) The finds found to date are a significant proportion of the beach population, whichinterchange slowly with sub-sea populations and hence cannot be treated as a singlepopulation.d) The proportion of the find populations found to date varies between find categoriesand can be a significant proportion of the find populations, which interchange slowlywith sub-sea populations and hence cannot be treated as a single population.The evidence to date would suggest that option (d) is the most probable scenario. Thehypothesis that proportion of the find populations found to date varies between findcategories and can be a significant proportion of the find populations is supported by thedrop in stone and beta-rich find rates. Stones were found at an average rate of 0.44 per habefore the 2010/11 financial year and 0.11 per ha during 2010/11. Beta-rich find rates were0.69 per ha up to the start of the 2010/11 financial year and 0.19 per ha during 2010/11. Thehypothesis that the interchange rate between sub-sea and the beach is slow is supported byabsence of high activity finds (which have been recovered in previous years) that haverepopulated the beach from the sub-sea reservoir. The more sensitive Groundhog TM Synergymonitoring system is finding lower activity alpha-rich particle finds that those found earlierusing the Groundhog TM Evolution 2 system. Superimposing the histograms of the separateEvolution 2 and Synergy transformed log normal data sets shows than the Evolution 2 datawas biased to higher 241 Am activities compared to the Synergy data (Figure 3.13). The 98percentile activities values confirm this conclusion with Evolution 2 activity being 2.6E+05 Bqcompared to the Synergy activity of 8.3E+04 Bq. If the repopulation rate were significant,then the Synergy and Evolution 2 values should be comparable or reversed with the moresensitive Synergy detecting a wider range of activities.© Nuclear Decommissioning Authority 2011. 39

SSEM/2011/4730 June 2011Log Am241 Activity Histogram of Separate Evolution 2 and Synergy Particle Data706050Frequency4030201003 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6Log to base 10 of Am241 ActivityEvolutionSynergyFigure 3.13. Histogram of Log Normally Transposed Alpha Rich Particle 241 Am Activities forseparate Evolution 2 and Synergy Monitoring Periods.Further work with the statistical techniques advised in the first statistics report (Scott andTyler, 2011a) should provide evidence that can confirm or deny this hypothesis.A report on the assessment of the potential sources of alpha-rich finds, commissioned by theParticle Sources & Pathways Working Group (PSPWG), was completed in June 2010(Hackney ., 2010). The report used 238 Pu and 241 Am data on 51 alpha-rich finds that wereavailable at the end of March 2009. It identified that the bulk of these finds had their origins indistinct Magnox or Oxide fuel types. Since March 2009 a further 43 results have becomeavailable. These 43 finds have been categorised using the factors developed in the report,and are shown in Table 3.7 below.Table 3.7. Alpha-rich sub-group numbersAlpha-rich sub category Original Report New dataMagnox 25 3Oxide 23 27Unresolved 3 13When compared to the original data, the new data shows a marked increase in the Oxidegroup numbers and a drop in Magnox group numbers. This observation is consistent with thelower mean alpha activity for particles found since the introduction of the Synergy monitoringsystem in August 2009. That is, the mean 241 Am activity of all 50 Oxide finds (i.e. 6.31E+04Bq) is less than 50% of the mean activity for the 30 Magnox finds (i.e. 1.34E+05 Bq); so theOxide subgroup might be expected to be more prevalent in lower activity finds found bySynergy than the Magnox subgroup.© Nuclear Decommissioning Authority 2011. 40

SSEM/2011/4730 June 2011Histogram and probability plots of the SL actinide ratio data for the Magnox and Oxidesubgroups show that the ratios are normally distributed with a standard deviation of 20% ormore. To assess the extent of this uncertainty a scatter plot was generated that showed theerror bars based on the analytical measurement uncertainties (Figure 3.14). The axis valuesof this plot have been removed to avoid restricting this document. Their absence does notaffect the conclusion that the Magnox subgroup is relatively well resolved and the Oxidesubgroup less so. The error bars for the unresolved group could place them in either theMagnox or Oxide groups, which could imply that there are few, if any, mixed Magnox andOxide finds. To check if a more refined assessment could be undertaken using the NPLanalysis the 16 alpha-rich finds from the second and third tranches were plotted (note thatthe 238 Pu uncertainty values were not available for the first tranche. No noticeableimprovement was seen using the NPL data compared with the SL data, with the SL databeing better for the Magnox subgroup. Figure 3.15 shows the same data without error barsso the find positions on the graph are more easily seen.Beach Find Origin AssesmentOxide origin findsAm241 / Pu239 RatioMagnox origin findsFinds outside ovals are unresolved or of mixed Magnoxand Oxide originsPu238 / Pu239 RatioOxide origin Magnox origin Unresolved or mixed origin NPL DataFigure 3.14. Alpha-rich Find Subgroups Based on their Actinide Activity Ratios© Nuclear Decommissioning Authority 2011. 41

SSEM/2011/4730 June 2011Beach Find Origin AssesmentOxide origin findsAm241 / Pu239 RatioMagnox origin findsFinds outside ovals are unresolved or of mixed Magnoxand Oxide originsPu238 / Pu239 RatioOxide origin Magnox origin Unresolved or mixed origin NPL DataFigure 3.15. Alpha-rich Find Subgroups without Error Bars.In conclusion, the additional finds are judged to support the original report conclusions, asfollows: The most likely source of alpha-rich finds is historic spent fuel reprocessing operationsfrom the mid 1960's to prior to the mid 1980s with age estimates ranging from 25 to 45years, 35 years being typical. The most likely pathways are all associated with authorised historic liquid effluentdischarges, with the particles formed from finely dispersed ferric hydroxide floc. Improvements in liquid effluent management from the mid to late 1980s resulted in theferric hydroxide floc material being filtered out of the liquid effluent after this date.The assessed correlation of the 241 Am activity against particle volume was reported in thesecond beach monitoring report (D’Souza, 2010). This analysis has been updated with thenew data from the third tranche of finds sent for further analysis by NPL. The inclusion ofthese 6 finds in the correlation analysis made very little difference to the regression statistic,with the R values quoted to 2 decimal places being the same as the original analysis (i.e. Rvalue remaining at 0.89). This confirms that there is a strong correlation between the volumeof an alpha-rich particle and its 241 Am activity. If the characteristics of a group of finds can be fitted to a statistical distribution then a widerange of statistical techniques can be employed. If an adequate fit cannot be achieved thenthe analysis is limited to less powerful non-parametric techniques. For alpha-rich finds anobvious starting point is the particle activity.Figure 3.16 and Figure 3.17 are simple histogram plots of the log base 10 transformed 241 Amactivities for separate and combined data respectively, collected during both Groundhog TMEvolution 2 and Groundhog TM Synergy monitoring periods. The bias to the higher activities,© Nuclear Decommissioning Authority 2011. 42

SSEM/2011/4730 June 2011mentioned in the section above, can be seen in the Evolution 2 data compared with Synergy.The larger data set for Synergy (i.e. 454 particles) dominates the distribution compared toEvolution 2 (i.e. 60 particles).Log Am241 Activity Histiogram of Separate Evolution 2 and Synergy Data706050Frequency4030201003 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6Log to base 10 of Am241 ActivityEvolutionSynergyFigure 3.16. Separate Evolution 2 and Synergy 241 Am Activity Histogram.Log Am241 Activity Histogram706050Frequency4030201003.00E+003.10E+003.20E+003.30E+003.40E+003.50E+003.60E+003.70E+003.80E+003.90E+004.00E+004.10E+004.20E+004.30E+00Log to base 10 of Am241 Activity4.40E+004.50E+004.60E+004.70E+004.80E+004.90E+005.00E+005.10E+005.20E+005.30E+005.40E+005.50E+005.60E+005.70E+005.80E+005.90E+006.00E+00Figure 3.17. Combined Evolution 2 and Synergy 241 Am Activity Histogram.The plutonium isotope analysis for alpha-rich particles shows a similar log normal distribution(Figure 3.18 and Figure 3.19. With less Plutonium data available compared to 241 Am theshape of the distribution is not as well defined as for 241 Am. That is, 514 particles wereincluded in the 241 Am activity plot compared to 109 for the 239 Pu activity plot and 84 for the238 Pu activity plot. In addition to the effect of the lower numbers of Plutonium results, theiranalysis also have moderately large uncertainties compare to 241 Am analysis.© Nuclear Decommissioning Authority 2011. 43

SSEM/2011/4730 June 2011Log Pu239 Activity Histogram12108Frequency6420Figure 3.18. 239 Pu Activity Histogram.3.00E+003.10E+003.20E+003.30E+003.40E+003.50E+003.60E+003.70E+003.80E+003.90E+004.00E+004.10E+004.20E+004.30E+004.40E+004.50E+004.60E+004.70E+004.80E+004.90E+005.00E+005.10E+005.20E+005.30E+005.40E+005.50E+005.60E+005.70E+005.80E+005.90E+006.00E+00Log to base 10 of Pu239 ActivityLog Pu238 Activity Histogram141210Frequency864203.00E+003.10E+003.20E+003.30E+003.40E+003.50E+003.60E+003.70E+003.80E+003.90E+004.00E+004.10E+004.20E+00Figure 3.19. 238 Pu Activity Histogram.4.30E+004.40E+004.50E+004.60E+004.70E+004.80E+004.90E+00Log to base 10 of Pu238 Activity5.00E+005.10E+005.20E+005.30E+005.40E+005.50E+005.60E+005.70E+005.80E+005.90E+006.00E+00To more accurately assess if 241 Am activity in alpha-rich particles is log normally distributed astatistical probability plot (Figure 3.20) can be used. This type of plot displays the log activityplotted against the cumulative find percentage and shows the fit across the whole of thedistribution with the median activity being at the 50% point. Finds that follow the fitteddistribution (i.e. the central blue line) would represent a perfect fit and finds within the outerblues lines are within the 95% confidence interval. A curve in the tail indicates a skeweddistribution and a point far away from the line an outlier. The probability plot also gives theAnderson-Darling statistic (AD), which is a powerful statistical measure of normality. For thelog normal hypothesis to be rejected the p value must be less than or equal to the chosenstatistical alpha-level (i.e. for hypothesis testing an alpha-level of 0.1 corresponding to a 10%chance of rejecting the log normal hypothesis when it is true). A probability value greaterthan 0.1 would support the hypothesis that the 241 Am activity in alpha-rich finds is log normaldistributed. Note that for comparison, fitting the same data to a normal distribution (plot notshown) gives p < 0.05. In this case, if the null hypothesis was that the 241 Am activity in alpharichfinds was normally distributed it would be rejected in favour of the alternative hypothesisthat it is not normally distributed.© Nuclear Decommissioning Authority 2011. 44

SSEM/2011/4730 June 2011Figure 3.20. Probability Plot of Log of 241 Am Particle Activity (no LOD values in data set).Figure 3.21. Probability Plot of Log of 239 Pu Particle Activity (positive data only).© Nuclear Decommissioning Authority 2011. 45

SSEM/2011/4730 June 2011Figure 3.22. Probability Plot of Log of 238 Pu Particle Activity (positive data only).From the plots and statistics above all three radionuclides show a strong correlation to a lognormal distribution with p values greater than 0.1. The Anderson-Darling test is heavilyweighted at the tails which explains the lowest p value being seen for 241 Am. Figure 3.20shows that the upper end of the 241 Am activity is under represented and the lower end overrepresented. The 238 Pu and 239 Pu activity plots (Figure 3.21 and Figure 3.22) show similarunder representation at the higher activities with some indication of over representation atlower activities for 238 Pu. Of the three radionuclides 241 Am is the critical radionuclide fordetection by the Groundhog TM Synergy system. The over representation at lower 241 Amactivities would suggest that Groundhog TM Synergy is capable of detecting all members ofthis population of alpha-rich finds and the limit of detection (LOD) is not an issue. To confirmthis conclusion a probability plot (Figure 3.23) of just the particles found at the sand surfacecan be assessed.© Nuclear Decommissioning Authority 2011. 46

SSEM/2011/4730 June 2011Figure 3.23. Probability Plot of Log of 241 Am Activity for Particles found at the Sand Surface.In this case if the lower 241 Am activity of the alpha-rich population was lower than theequipment LOD then they would be easier to detect on the surface. A surface probability plotwould therefore show a more significant over representation at the lower end than the plotusing data from all particle depths. A comparison between Figure 3.20 and Figure 3.23shows that this is not the case; with the plot of particles on the surface giving a similarpattern to that for particles from all depths. This supports the conclusion that theGroundhog TM Synergy monitoring equipment is capable of detecting the whole range of241 Am activities in the alpha-rich find population, depending on the depth of the find, and thatequipment LOD is not an issue. Further work on fitting statistical distributions to the alpharichdata is planned using data modified by the detection efficiency, as suggested by thestatistical support contract (see section 3.2.2.4).Table 3.8. Basic statistics for actinide activities based on log normally distributed data.Radionuclide => Ln 241 Am Ln 239 Pu Ln 238 PuMean 10.15 9.67 9.64Standard Deviation 0.76 0.86 0.65Q1 9.65 9.08 9.17Median 10.13 9.66 9.63Q3 10.62 10.19 10.05Minimum 7.70 7.89 8.52Maximum 13.36 12.64 11.39Skewness 0.19 0.35 0.57Kurtosis 0.80 0.63 0.39N 514 92 67© Nuclear Decommissioning Authority 2011. 47

SSEM/2011/4730 June 2011Table 3.9. Basic statistics data in 3.8 converted from the natural log values back to activities.Radionuclide =>241 Am Activity(Bq)239 Pu Activity(Bq)238 Pu Activity(Bq)Mean 2.55E+04 1.58E+04 1.53E+04Q1 1.56E+04 8.73E+03 9.59E+03Median 2.52E+04 1.57E+04 1.52E+04Q3 4.08E+04 2.66E+04 2.31E+04Minimum 2.20E+03 2.68E+03 5.01E+03Maximum 6.34E+05 3.09E+05 8.81E+04One particle has been found on Drigg beach with a combination of processed actinidematerial (i.e. 4.48E+03 Bq of 241 Am) and activation products (i.e. 8.65E+03 Bq of 60 Co). Thisfind was recovered in October 2007 and no further finds of this type have been recoveredsince this date. There are no site processes that combine these two radionuclides so this findwas probably formed within the effluent system from a combination of waste streams.Six alpha-rich stones have been found on the Sellafield beach with processed actinideactivity (i.e. 241 Am); two of which also had fission product activity (i.e. mainly 137 Cs but onewith a small amount of 154 Eu). The most probable source of these finds is the absorption ofactivity from the authorised discharges from the Sellafield pipeline. The stones may havebeen in close proximity to a hole in the pipeline over an extended period of time and thenreleased during the pipeline removal project(s).A beta-rich find sub-group assessment report is currently in draft awaiting further data fromSerco. Up to the 31/03/2011 428 beta-rich finds have been categorised as stones and 270 asparticles, with 27 of these particles also categorised as excess beta-rich. The radionuclideactivity is almost completely attributed to 137 Cs with low levels of other radionuclides presentin a small number of finds. As the data is more limited than that available for alpha-rich findsit was not possible to use the approach taken for the source identification of alpha-rich findsfor the beta rich finds. The age of a mixed fission product source can be estimated if both134 Cs and 137 Cs isotopes are present and the fuel source is known. In this case, the 134 Csactivity estimates are almost all at the limit of detection and the fuel source is not known. Thebest age estimate that can be achieved is therefore based on a default Magnox referencefuel type and LOD 134 Cs results, which gives a find age of greater than 16 years old. As thisage is greater than 16 years it can not be directly compared with the 35 years estimated foralpha-rich finds. The limiting factor in the age calculation comes from the short 134 Cs half lifeof just 2 years compared to the 30 year half life for 137 Cs. Table 3.10 shows how quickly the134 Cs half life becomes critical with the Caesium isotope ratio becomes very large after 15years.© Nuclear Decommissioning Authority 2011. 48

SSEM/2011/4730 June 2011Table 3.10. Beta-rich Caesium Isotope Decay Factors.Time After Reprocessing(years)Percentage Activity Remaining137 Cs134 Cs137 Cs / 134 Cs Ratio0 100 100 11 97.72 71.46 1.372 95.49 36.50 2.623 93.32 13.32 7.014 91.19 3.47 26.255 89.11 0.65 137.6310 79.41 0.02 3530.3815 70.76 1.46E-04 4.86E+0520 63.05 1.76E-07 3.59E+0825 56.19 3.95E-11 1.42E+1230 50.07 1.66E-15 3.02E+16Table 3.11 gives an estimated age range for beta-rich finds based on Magnox reference fueltype.Table 3.11. Beta-rich Find Estimates.137 CsActivity (Bq)Corresponding 134 CsActivity (Bq) 1Estimated Age(years)137 Cs Mean 1.20E+04 2.24E+01 Greater than 15.7137 Cs Maximum 2.92E+05 1.06E+02 Greater than 20.9137 Cs Minimum 4.75E+02 3.71E+01 Greater than 3.7 21. The age estimates are greater than the calculated value as all the 134 Cs values are at the analysis limitof detection.2. This was an excess beta-rich find with a low 137 Cs activity, which resulted in the low age estimate.A similar assessment to the alpha-rich correlation with particle volume was undertaken forbeta-rich particles. In this case the 137 Cs activity was found to be more strongly correlated toparticle surface area than to particle volume. As the difference between the surface area andvolume correlation was small, the assessment was extended beyond the use of all availabledata to finds with a volume greater than 1 mm 3 and finds with a volume less than 1 mm 3 . Thecorrelation R values for all three assessments were consistently higher for surface areacompared to volume by a small amount for each of these groups (i.e. R SA /R V = 0.55/0.54,0.59/0.50 and 0.80/0.76 respectively). The reasons for the small difference can be postulatedas being due to finds created in layers or the activity absorbed towards the centre of theparticle in very porous materials. A further limitation of the analysis was that it was based ondata from only 20 finds due to the difficulty in estimating particle dimension for smallparticles. This analysis will be updated when the tranche 3 analysis data becomes available. In a similar way to the alpha-rich finds an obvious starting point for a beta-rich finddistribution assessment is to look at simple histogram plots of log transformed 137 Cs activitydata. In this case there are significant numbers of both stone and particle beta-rich finds so© Nuclear Decommissioning Authority 2011. 49

2.52.72.93.13.33.53.73.94.14.34.54.74.95.15.35.55.75.96.16.36.52.52.72.93.13.33.53.73.94.14.34.54.74.95.15.35.55.75.96.16.36.5SSEM/2011/4730 June 2011histograms for both are given in Figure 3.24 and 3.25 respectively. The activity data used forthe histogram plots has been transformed using a log base 10 transformation to show theshape of the distribution more clearly. There are 428 data points for stones and 270 forparticles and all the analysis results are greater than the limit of detection.Log Stone Cs137 Activity Histogram45403530Frequency2520151050Log to base 10 of Cs137 ActivityFigure 3.24. 137Cs Stone Activity Histogram.A tail at higher activities is observed for stones that may be due to random outliers (~ 2% oftotal) but is more probably due to either overlapping populations of beta-rich stones (i.e. twoor more populations with overlapping activity ranges) or an unusual 90 Sr to 137 Cs ratio or apopulation that does not fit a statistical distribution type.Log Particle Cs137 Activity Histogram353025Frequency20151050Log to base 10 of Cs137 ActivityFigure 3.25. 137 Cs Particle Activity Histogram.There are fewer outliers for particles compared with stones. It is expected that the outliers inboth groups will result in a poor fit to their corresponding log normal probability plots. Theprobability plot for stones (Figure 3.26) has a probability p value of < 0.05 and hence the log© Nuclear Decommissioning Authority 2011. 50

SSEM/2011/4730 June 2011normal distribution hypothesis would be rejected. The corresponding particle plot (Figure3.27) gives better hypothesis testing statistics and the log normal distribution of 137 Cs activityin beta-rich particles would be accepted. The plots show a similar under representation athigher activities but differ at the lowest activities with stones being under represented andparticles being over represented. The beta-rich particles show a similar pattern to that foundfor alpha-rich 241 Am activity.Figure 3.26. Probability plot of Log of 137 Cs Stone Activity.Figure 3.27. Probability plot of Log of 137 Cs Particle Activity.As for alpha-rich particles, further work on fitting distributions to beta-rich particle data isplanned using data modified by the detection efficiency, as suggested by the statisticalsupport contract (see section 3.2.2.4).© Nuclear Decommissioning Authority 2011. 51

SSEM/2011/4730 June 2011In summary, the 137 Cs activities in particles appears to be log normally distributed; asummary of the basic statistics is given in the Table 3.12 and Table 3.13 below. For stonesthe log normal distribution is not proven but the basic statistics are given for comparison withparticles.Table 3.12. Basic statistics for 137 Cs activities based on log normally distributed data.Find type => Stones ParticlesMean 4.32 4.08Standard Deviation 0.47 0.38Q1 4.00 3.82Median 4.28 4.06Q3 4.63 4.31Minimum 3.29 2.68Maximum 6.02 5.47Skewness 0.60 0.07Kurtosis 0.69 0.89N 428 270Table 3.13. Basic statistics data in Table 3.12 converted from the natural log values back toactivities.Find Type =>Stones ActivityParticles Activity(Bq)(Bq)Mean 2.11E+04 1.20E+04Q1 9.90E+03 6.57E+03Median 1.90E+04 1.15E+04Q3 4.27E+04 2.06E+04Minimum 1.95E+03 4.75E+02Maximum 1.04E+06 2.92E+05The above statistics show that the beta-rich 137 Cs activities have a greater range than thecorresponding 241 Am activity for alpha-rich particles. They show that the Groundhog TMSynergy system is capable of detecting beta-rich finds down to activities that correspond tovery low risk.There are more unusual beta-rich finds than alpha-rich finds. A brief summary is given below. 11 stones with maximum activities of ~5E+03 241 Am and ~9E+05 Bq 137 Cs2 particles with maximum activities of ~1E+03 241 Am and ~3E+04 Bq 137 Cs 2 stones with maximum activities of ~5E+02 60 Co and ~8E+03 Bq 137 Cs1 particle with activities of ~2E+02 60 Co and ~2E+04 Bq 137 Cs© Nuclear Decommissioning Authority 2011. 52

SSEM/2011/4730 June 2011 There are only 13 60 Co rich finds, 12 of which are particles and is 1 a stone. The 60 Coactivities have a fairly narrow range from ~6E+03 Bq to ~2E+04 Bq. The stone activity was atthe top end of this range. It is judged that there are too few data points for a meaningfulstatistical analysis.One particle is judged to be unusual as it contained 4E+03 Bq 241 Am and therefore was alsocategorised as alpha-rich. It was included in the unusual alpha-rich section above.The details for all finds in this group will be provided in the beta-rich sub-group report somembers of the Particle Sources & Pathways Working Group can see if they can possiblyexplain how, when and where they were created.There are only 28 excess beta-rich finds, 27 of which are particles and a single stone. Thestone contain natural 226 Ra activity and was judged to be a granite chip from the adjacentrailway bed. The 137 Cs activities range from ~5E+02 Bq to ~6E+04 Bq. Although 23 of thesefinds have been sent to Serco for further analysis it is judged that there are too few datapoints for a meaningful statistical analysis. At present the definition of excess beta-rich is auseful indicator of the presence of 90 Sr but is insufficient to accurately predict 90 Sr activities.If the granite chip is ignored only one particle is judged to be unusual as it contained ~7E+02Bq 241 Am. This activity is relatively low at approximately 3 times the mean analysis limit ofdetection (i.e. < 2.7E+02 Bq 241 Am). Although only one particle would be judged as unusualwith respect to the excess beta-rich group they can all be judged as unusual with respect tothe beta-rich group.The SL gamma scan, NPL separated find gamma scan and NPL total dissolution activitiesare in close agreement. In addition the NPL results have shown:• Alpha-rich particle activity is mainly due to Plutonium isotopes and 241 Am. TheEDX results of the particle surface would suggest that Plutonium and Americiumare co-located.• Beta-rich particle activity is mainly due to 137 Cs together with 90 Sr, with a 90 Sr:137 Cs ratio range of 0.04 to 0.91. Approximately half (i.e. 24 out of 47) beta-richparticles had a 90 Sr activity greater than 10 % of the 137 Cs activity.• Destructive analysis confirmed the separated particle gamma scan results.Dose rates measured with a SmartIon Ion chamber have shown:• Gamma dose rate measurements are generally low (i.e. < 2 microSv/h) with amaximum of 0.9 microSv/h for alpha-rich particles and 11 microSv/h for beta-richparticles.• Beta/gamma dose rates for alpha-rich are between 1 microSv/h and 5.9microSv/h and for beta rich particles between 1 microSv/h and 680 microSv/h.• The tranche 3 contract will provide an explicit SmartIon dose rate to skin dosecalibration for comparison with a literature derived conversion multiple of 95 usedfor the first two reports (Cowper ., 2009; Clacher et al., 2010).Density measurements for the first tranche of finds were calculated using mass anddimension estimates. For the second tranche an improved haloalkane immersion techniquewas used. The density measures have shown:• Alpha-rich particle densities are low with an average density less than 2 g/cm 3(i.e. typical of silicates, carbonate minerals, and igneous rocks). A few alpha-rich© Nuclear Decommissioning Authority 2011. 53

SSEM/2011/4730 June 2011particles had densities from 2.4 g/cm 3 to 3.3 g/cm 3 , which is most probably due tothe presence of iron oxide (density 5.17 g/cm 3 ) that was detected by the EDXscans.• The beta-rich particles had a wider range of densities with the higher valuesassociated with very small particle sizes from the first sample tranche. For thesecond tranche density estimates were not made on very small particles as theirresults were judged to be unreliable. The average beta-rich particle density was2.7 g/cm 3 with a range of 1.9 g/cm 3 to 6.8 g/cm 3 . The higher end of this range isconsistent with iron oxide (density in range 5 g/cm 3 to 6 g/cm 3 ) as identified on thesurface of particles by EDX.• The pebbles and stones, from the first tranche, had an average density of 2.3g/cm 3 with a range from 1.7 g/cm 3 to 3 g/cm 3 . This is consistent with theidentification of sandstone, siltstone, tuff, and igneous rocks. Most pebbles andstones are beta-rich but there are a few alpha-rich stones. The stone (about 5 mmin length) with the highest 241 Am activity (i.e. 5.1E+05 Bq) was included in thelatest analysis tranche. This has a density of 1.24 g/cm 3 and has a high Carbonand Oxygen content in its surface by EDX.Particle structure based on Alicona and SEM images have shown:• Particles have shapes and surface textures that range from the expected roundedplate and spheres to unexpected rough, jagged, or cracked fragments; sometimescombined in groups. Two particles were wire-like metal swarf (with high 60 Co,Iron, Chromium, and Nickel content i.e. stainless steel). Particles with highZirconium content varied from solid rounded stone like chips to conglomerates ofsmall particles.• Particles may have been in the environment for many years with the NPL ageestimates ranging from 32 to 48 years based on a simple calculation of the ingrowth of 241 Am from the decay of 241 Pu. Considering the particle ages, they aremore fragile than expected with Electron microscope and Alicona imagingshowing fractured solids (that separate into several particles when handled) andconglomerates of small particles welded together (that can completely fragmentwhen handled). The fragility of the particles affected both alpha-rich and beta-richparticles but has been more problematic for the tranche 3 alpha-rich particles thatare undergoing sequential leaching and SEM/EDX measurements. The examplein Figure 3.28 below is part of a beta-rich particle from tranche 2.Figure 3.28. SEM Image of part A of beta-rich particle IM090340.© Nuclear Decommissioning Authority 2011. 54

SSEM/2011/4730 June 2011Particle chemical composition based on EDX measurements of the surface have shown:• EDX scans focus on a point of interest or a small area and can therefore varysignificantly over the surface of a single particle. This variation may be due tochanges in the surface composition or the shielding affects of other materialsstuck to a particle surface. For example, the interfering presence of salt crystalson the particle surface has reduced the information available for tranche 1 and 2particles. To solve this problem tranche 3 particles have been washed prior toEDX measurements.• Iron oxide is strongly represented in both alpha-rich and beta-rich particles, as issilica and calcite.• Aluminium is present, with the highest concentration associated with a highlyfragmented particle.• The two metallic particles that have a metallic swarf appearance havecomponents found in stainless steel.• Zirconium is present in a range of concentrations but mostly either high (i.e. >80%) or low (i.e.

SSEM/2011/4730 June 2011• Boron, Barium, Calcium, sodium, magnesium were the most significant elementsdetected.• The contamination problem is being addressed for tranche 3 analysis. Thetranche 3 results will provide quality trace metal analysis for both alpha-rich andbeta-rich particles that will facilitate the characterisation of the particles and maysuggest their origins.The Health Protection Agency's (HPA) rat studies key findings (Pellow ., 2010)has shown:• The intestinal absorption factor (f 1 ) for 10 alpha-rich particles ingested by ratsgave the following results. For comparison ICRP 72 default f 1 value are the samefor all these radionuclides at 5E-04.Table 3.14. f 1 factors derived by HPA in-vivo intestinal absorption study.RadionuclideUptake range (f 1 factor)238 Pu 1.7E-07 to 1.7E-05239/240 Pu239 1.5E-07 to 2.4E-05241 Am 4.0E-08 to 1.8E-05• The HPA recommends that an f 1 factor of 3E-05 be used for alpha-rich beachparticles containing 238 Pu, 239/240 Pu and 241 Am. Note that this f 1 value has beenused in the HPA beach finds risk assessment for all age groups except the 3month infant, where a more conservative figure of 3E-04 was used (Oatwell .,2011).• The derived ingestion dose factor using this value for f 1 in the ICRP 30 gut modelis 1.9E-08 Sv/Bq. Note that ICRP 30 gut model was preferred by HPA for theirrisk assessment compared to the new ICRP 100 human alimentary tract model(Oatwell ., 2011)• This dose factor equates to a committed effective does of 1.9 mSv for theingestion of a 1E+05 Bq alpha-rich particle from beaches in the vicinity ofSellafield.The GIS location maps in this report show the power of a visual interpretation of the beachfind data. GIS has also been a very valuable tool for answering specific questions andhelping to focus the monitoring programme.GIS has been used to identify differences in find locations of alpha-rich particle subgroupssuch as differences in Oxide and Magnox origin. These subgroups are those identified in thereview of alpha-rich finds (Hackney et al., 2010) and indicate the most probable origin of thefind with respect to the original fuel type. GIS shows that finds in the Magnox subgroup areall very close to the pipeline compared to those in the Oxide group. If this observation iscorrect for all alpha-rich particle finds then the bulk of these finds would be of Oxide fuelorigin. That is, based on the Oxide and Magnox ratios in each distance bin (i.e. 2 kmdistance blocks) then 412 alpha-rich particle finds would be of Oxide fuel origin and 102 ofMagnox fuel origin. This can be simply shown in the histogram below (Figure 3.30).© Nuclear Decommissioning Authority 2011. 56

SSEM/2011/4730 June 2011Alpha-rich Particle Distance from Sellafield Pipeline5040173 finds216 finds50 finds30Frequency20100-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24Distance in Km (positive is North, negtive is South)Oxide-50 finds Magnox-17 finds Alpha-rich- 514 findsFigure 3.30. Alpha-rich Particle Find Distances from the Sellafield pipeline.Further work is planned to improve understanding the uncertainties associated with theMagnox and Oxide designations for each find based on SL and NPL analysis data. With thisrefined data the apparent Oxide alpha-rich particle find correlation with distance will bereviewed.Another example of how GIS can be employed is the query concerning finds found in theoverlap area between monitoring transects. This analysis can provide information onrepopulation rates and the potential for finds to be located in undisturbed sand strata. Theinterim results of this analysis, for the Sellafield beach area over the 2010/11 financial year,are summarised in Table 3.15 and Table 3.16 below. The monitoring transects are definedas the area monitored within a tide cycle and by default are the daily monitoring areas.Monitoring transects that overlap were identified using GIS extents, which have a 2 metreboundary around monitoring points. The find location within the overlap area was thencompared to the nearest height data points for both monitoring periods. Height data are notnecessarily co-located for each period but were found to be less than 30 cm from the findlocation and often much closer. The transect overlapping with the find transect are definedas; 'before' overlap - for a monitoring period before the period in which the find was found'after' overlap - for a monitoring period after the period in which the find was found'before and after' overlap - for monitoring periods both before and after the period inwhich the find was found.© Nuclear Decommissioning Authority 2011. 57

SSEM/2011/4730 June 2011Table 3.15. Overlap find numbers summary for Sellafield beach monitoring in 2010/11.Number of instances of finds found in areasOverlap Survey Typethat were surveyed before or after the findrecoveryAlpha-rich Beta-rich TotalBefore overlap survey 20 4 24Before and after overlap surveys 4 2 6After overlap survey 18 9 27No finds were found in all 51 cases in the overlap areas in the 'after overlap' monitoringperiods, which would support a low repopulation rate. To investigate this in more detail anassessment was made of the height difference between the find depth in the sand and theheight of the sand surface during a previous monitoring period (i.e. the before). This wascompared to the limit of detection for the find activity, which indicated if the find should havebeen found during the previous survey. The outcomes to this assessment are:• The find could possibly have been in an existing stratum that was below thedetection capability of the equipment during the previous survey (i.e. outside LODrange).• The find repopulated the area after the previous survey.These options are shown in Figure 3.31 and summarised in Table 3.16 below.Scenario 1 - Previous beach level higher than find level by more than LODScenario 2 – Previous beach level higher than find level but less than LODDifference greater than LODFind levelDifference less than LODScenario 3 - Previous level lower than find levelFigure 3.31. Find Overlap Outcomes.Table 3.16. Before Overlap Survey Analysis for Finds within Equipment LOD Range.Reason for find being in locationAlpha-rich 1 Number of findsBeta-rich 2 TotalFind possibly in existing stratum - scenario 1 5 0 5Find could be either in existing stratum or2 3 5repopulated area - scenario 2 or 3Find repopulated area - scenario 3 13 1 14Total 20 4 241. Sand difference values for alpha-rich finds - Scenario 1 greater than 5 cm, Scenario 2 greater than 0 cm ANDless than or equal to 5 cm, Scenario 3 less than 0 cm.2. Sand difference values for beta-rich finds - Scenario 1 greater than 30 cm, Scenario 2 greater than 0 cm ANDless than or equal to 30 cm, Scenario 3 less than 0 cm.© Nuclear Decommissioning Authority 2011. 58

SSEM/2011/4730 June 2011The data used for this initial assessment were limited to Sellafield beach areas because findrates at other beaches were too low for meaningful analysis, but supports the hypothesis thatrepopulation is significant for the Sellafield area for alpha-rich finds. Linking this conclusion tothe low interchange rate between the beach and sub-sea proposed earlier would suggestthat finds are predominately moved around from other areas of the beach by tidal action.Further work is planned on automating the GIS overlap assessment tool to help refine thisconclusion.Two reports have been received on statistical techniques that can be employed for theanalysis of beach monitoring data. The first report (Scott and Tyler, 2011a) givestechniques that can be employed to characterise beach finds and the second (Scott andTyler, 2011b) gives guidance on the best 'statistical' monitoring system for future beachmonitoring programmes. The reports' recommendations and the initial SL response aregiven in the Table 3.17 and Table 3.18 below.Table 3.17. Statistical techniques report recommendations.Recommendations1 Systematic sampling areas required. The spatialheterogeneity of particle distribution may begoverned by sedimentological processes ofbeach accretion/erosion and particle selectivitythrough systematic processes of sorting (or lackof) of grain size. Non systematic sampling ofbeaches may lead to bias in the estimatedparticle density. In reporting the sampling effort,and to provide a basis for assessing thesystematic coverage of monitoring, it is importantthat the monitoring effort be reported as afootprint and as a proportion of the total availablearea on the beach. Comparison of successivefootprints will provide a basis for assessingsystematic coverage, i.e. contiguous areas arecovered and the frequency with which areas ofthe beach are sampled.2 Systematic temporal sampling of beachesrequired. The temporal heterogeneity of theparticle population may change with time,specifically the seasonality of tidal and waveenergy. Estimating particle density without atemporal perspective may result in an under oroverestimate in particle abundance.SL initial responseThe current reporting system is based on analpha-rich find footprint (i.e. it is judged thatthe 5cm to 10 cm turnover of sand over asingle tide will provide fresh area with respectto monitoring for 241 Am; which has a limit ofdetection of 1E+05 Bq at 5 cm depth). Thisrecommendation will be reviewed with respectto reporting radionuclide specific footprintsover radionuclide specific monitoring periods.There is little evidence of a seasonal affect inthe current data. The 2011/12 monitoringprogramme includes repeat areas forSellafield, St Bees, Braystones and Seascalebeaches. Sellafield beach, which isprogrammed for the most frequent monitoringand has the highest find rates, will providedata that should enhance the seasonalassessment capability. The repeat monitoringat St Bees (x5), Braystones (x3) and Seascale(x3) will provide additional supporting data.Future monitoring programmes will takeaccount of any seasonal affects found.© Nuclear Decommissioning Authority 2011. 59

SSEM/2011/4730 June 2011Recommendations3 The reconstruction of the likely particle abundanceon each beach and by monitoring event (or rangeof monitoring events – given possible influences ofthe variation in the natural background) will requireseparate assessments of detection capability. Thisis unlikely to be feasible if conducted empirically,but can be achieved through computation.However, this will require careful characterisationof the detector response to known sources atdifferent depths and geometries for a typicalmonitoring velocity. This may be achievedempirically or through validated Monte Carlosimulations. With such a characterisation coupledwith the triggering routines for each detector (andtype of detector), a relatively simple algorithm canbe developed to independently assess detectionprobability and detection limits for each monitoringmeasurement and depth (note a similar solutionwas derived for Dounreay). This will demonstratethe variation in detection capability spatially, withdepth and with time and thus provide thenecessary information on the probability ofdetection to assess the likely detected proportionof each type of particle over predetermined depth.4 If there is a small percentage of censored values,then we would suggest a Kaplan Meier approach,which provides a non-parametric estimate of thecensored value and which can then be substitutedwhen determining the summary statistics etc.When there is a greater percentage of censoredvalues (more than 30% but less than 50%), thenKM or ROS methods could be used.5 When system upgrades are implemented (e.g.change in software or detector system), beachtrials should be undertaken to provide thestatistical evidence base to interpret the influenceon long term time series data.6 Transformations (including use of the Box-Coxtransformation) be explored to improve validity ofany distributional assumptions.SL initial responseA Monte Carlo simulation report wascommissioned from the beach monitoringcontractor (NUKEM now called Nuvia) by SLin 2008. This report will be reviewed with theNuvia Groundhog TM technical expert to seehow it can be expanded to include theSynergy detection capabilities.The categorisation of the finds into alpharich,beta-rich, 60 Co-rich and excess beta-richeliminates the limit of detection problem.Alpha-rich, beta-rich and 60 Co-rich have noLOD values and excess beta-rich has just 3LOD 137 Cs results out of 30. Two of theseresults have no positive analysis and one is agranite chip with natural 226 Ra activity.Although LOD is not an issue for beach finddata, if the categorisation is considered, theadvice given will be considered on a case bycase basis.The negative affect that changes to themonitoring equipment or software has on theability to use statistical assessmenttechniques will be included in the BATassessment of the change. The limitations ofbeach trails to provide the statisticalevidence base needed to assess the changewill also be considered.The log normal transformation has beenshown to be successful for both alpha-richand beta-rich particle finds (see above).However, the Box-Cox and othertransformation will be considered.© Nuclear Decommissioning Authority 2011. 60

SSEM/2011/4730 June 2011Recommendations7 Standard statistical analyses (such as generallinear models, confidence intervals andhypothesis tests) be used to explore the beachfinds and where appropriate to draw inferencesconcerning the population distributions, factorswhich account for the variability in the finds andto summarise changes.8 For temporal comparability over monitoringcampaigns, time series of finds should beadjusted for monitoring effort and equipmentchanges (see also recommendation 3 and 5).9 To assess which beaches should have a highpriority from habit information. Monitoring ofthese beaches should have a substantiallygreater footprint (>50 %) consistently to providea better sample of the particle population onthese beaches at a frequency, which iscommensurate with the change in sedimentprofile height between monitoring events. Thischange in sediment height should becomparable to the detection capability for theparticle activities of concern (e.g. 100 kBq for137 Cs). Beaches with markedly lower particledensities and habit characteristics may bemonitored less frequently although morecomprehensively to provide a better estimate ofthe detectable particle population (see alsorecommendation 10).10 The particle density will be greatly influenced bythe depth over which number of particles isestimated. The target detection depth andmonitoring frequency should be designed toreflect the amount of sand and therefore depthof sand being exchanged with the offshoreenvironment (see also recommendation 9).11 Data layers exist for within window, backgroundcounts, detector height and beach height data.This provides the possibility of modeling andmapping detection capability (probability ofdetection and detection limit) for each locationon the beach, in a similar way as undertaken atDounreay (Tyler ., 2010). Such data shouldbe used to provide more particle specific insightinto the likely abundance of particles with depth(see also recommendations 3, 5 & 8).SL initial responseSome of these techniques have already beenemployed and will be expanded, as advised.See response to recommendation 3 and 5.Historically, the beach monitoring programmehas focused on high occupancy areas basedon the EA's habit reports. This has beencombined with monitoring of high find rateareas to give a balanced approach. It isjudged that the > 50% footprint has beenachieved for beta-rich finds containing 137 Csor 60 Co-rich finds as the 1E+05 Bq limit ofdetection for these radionuclides is 30 cm ormore. However, for 241 Am the 1E+05 Bq limitof detection is 5 cm making it impracticable toachieve a 50% footprint in the current beachareas over a period of a single tide. Thedefinition of footprint therefore needs to bedefined explicitly for Sellafield finds,recognising that it may be different from thatused at Dounreay. A request will be made tothe Environment Agency for the next HabitSurvey to provide more detailed habit datawith respect to the beach occupancy and use.The depth of sand on beaches between StBees and Drigg point is not explicitly known.Practical observations of the appearance anddisappearance of rocks on the Sellafieldbeach would suggest that an explicit sanddepth measurement over the 630 hectares ofbeach that can be monitored (or 1400hectares of total beach area) could not berealistically achieved. Consideration will begiven to a practical solution to this problem,such as, an assessment of beach depthbased on the additional data gathered duringthe more frequent visits to the main beachareas.To be considered for inclusion into statisticswork programme.© Nuclear Decommissioning Authority 2011. 61

SSEM/2011/4730 June 2011Recommendations12 Consideration to be given to maximise the use ofspatial methods of analysis and mapping.13 Evaluation of trends in finds is time series shouldbe carried out, but first the series need to beadjusted for monitoring effort (seerecommendations 3, 5, & 11). Statistical modelsshould then be used to account for seasonalityand for possible autocorrelations. In the firstinstance, regression type models would beappropriate, (such as ARIMA) models to explorechanges over the monitoring period.14 Multivariate statistical techniques includingcluster and discriminant analysis could be usedto explore these features further, and todistinguish possibly distinct populations of finds.SL initial responseTo be considered for inclusion into statisticswork programme.To be considered for inclusion into statisticswork programme.To be considered for inclusion into statisticswork programme.Table 3.18. Statistical sampling report recommendationsRecommendations1 Consideration should be given to whether thecurrent categorisation of particles also reflectsdifferences in other risk related properties, i.e.properties which may affect their longevity inthe environment and solubility within thehuman stomach.2 An assessment as to whether particles behavein a similar manner to the sediment withinwhich they are found. Simply, does the hostsediment have similar size and densitycharacteristics to particle.3 Full and quantified specification of objectiveswithregard to area, probability of detection forspecific radionuclides and to an appropriatedepth to be agreed. The depth should reflecthabit information and the temporal and spatialdynamic of the beach.4 Following an assessment of beach dynamics,particle abundances, beach users’ habits etc,the regulator and other agencies should specify(in consultation with other parties) a minimumbeach coverage, frequency and detectioncapabilities - depth and activity (which shouldbe reviewed regularly).SL initial responseIt is judged that the categorisation of finds ishelpful in assessing risk to the critical group. Forexample, significant effort that been expended inmeasuring the parameters of alpha-rich finds(i.e. the high risk group). Consideration is givento the relative risks of sub-groups as new databecomes available (e.g. Magnox vs Oxidesubgroups etc.).The variation in sand characteristics issignificant over the range of beaches monitoredand within individual beaches. To overcome thisproblem consideration is being given to thecharacterisation of sand in a pocket around thefind. This would give information on thesimilarities between the find and local sand andthe variation in sand between different locations.The objectives are reviewed before setting eachyear's monitoring programme, taking account oftechnical issues and learning from experience.Explicit analysis and statistical objectives will beconsidered when developing future workprogrammes and will be incorporated into themonitoring programme review.The regulator and other stakeholders require SLto propose a monitoring programme thatincorporates the minimum beach coverage,frequency, and detection capabilities - depth andactivity. Where possible this should be based ona statistical analysis but the statistical samplingreport recognises that there are limitations tothis approach. The 2011/12 repeat visits willallow further refinement to future monitoringprogrammes.© Nuclear Decommissioning Authority 2011. 62

SSEM/2011/4730 June 2011Recommendations5 With regard to the implementation of a beachmonitoring campaign using the existing detectorsystem, the most practicable in terms of individualbeach coverage, would be systematic samplingwhich is efficient and ensures an even coverage ofthe area of interest.6 It is critical that the system of monitoring remainsstable over time and consistently deployed toachieve as large a footprint as possible. When asystem is upgraded, it is important that the twosystems operate together for a short period ofoverlap to ensure that past data can be calibratedto ensure that they are equivalent to the newerdata being acquired OR beach trials are performedto compare detection capability.SL initial responseSystematic sampling has been incorporatedinto beach monitoring programmes but not ina consistent way since the start ofmonitoring. This consistency issue will beaddressed to maximise the benefits gainedfrom a systematic sampling regime.Greater consideration will be given duringthe annual BAT (formally BPM) review to theimportance of consistency of the monitoringtechnique with respect to statistical analysis.That is, the advantages of introducing a newmonitoring technique needs to be weighedagainst the increased uncertainty itintroduces to the statistical analysis of themonitoring results. The need for acomparison between existing and newmonitoring systems is recognised, forexample, it was as incorporated into theOctober 2009 beach trails for both Evolution2 and Synergy monitoring systems.Recommendations1 Success interpretation of the provenance (e.g.recent arrival or older particle having beenuncovered by erosion) abundance of finds andwhether there has been a systematic change,perhaps as a result of environmental disturbance,requires consistent and frequent monitoring.Interpretation of monitoring effort and the particledensity described also benefits from additionalinformation, including evidence of beach heightchange, the degree of spatial overlap withprevious surveys and an assessment of detectioncapability with space and time. Theimplementation of real time kinematic GPS canprovide additional suitable data to assess beachheight variation (if coverage is comprehensiveand undertaken at a suitable frequency). GISfootprint mapping will provide the quantitativespatial perspective of the frequency with whichareas of a beach are being monitored.2 Information about the current speed and direction(predominant and in storm) for the offshoreenvironment round Sellafield and other beaches.On particle characteristics, eg propensity to breakup.3.2.3 Analysis ConclusionsData RequirementSL initial responseThe current 2011/12 monitoring programmeincorporates repeat areas that are consistentlyand frequently monitored. The data andexperience gained from monitoring theseareas will help define future years’ monitoringprogrammes. A GIS programme has beendeveloped to show overlap areas and identifythe finds in these areas that are either lower orhigher with respect to the sand height duringthe previous monitoring period.The Aquadopp monitoring data, measuredadjacent to the end of Sellafield pipeline, andthe Sellafield meteorological data will bereviewed to identify the frequency andintensity of storms affecting beaches beingmonitored and relate this data to finds madeafter the storms.• The activity in alpha-rich particles is mainly due to 241 Am and Plutonium isotopes,which appear to be co-located based on EDX surface measurements. The EDXmeasurements would also suggest that the actinide activity is in cluster rather than© Nuclear Decommissioning Authority 2011. 63

SSEM/2011/4730 June 2011homogeneously spread throughout the volume of the particle (see current bun modelin Figure 3.29.• The assessment of the actinide activity has identified their source as historicprocessed Magnox and Oxide fuels, with the activity within a particle being eitherpredominately of Magnox origin, predominately of Oxide origin or a mixture of both.• The age of the alpha-rich finds is consistent with the Magnox and Oxide fuel typesprocessed between mid 1960 to the early 1980s and not to more recent fuelreprocessing (i.e. ages between 45 years and 25 years).• The actinide activity in alpha-rich particles appears to be log normally distributed andshows that the lowest 241 Am activities are close to the expected minimumGroundhog TM Synergy system’s limit of detection.• The HPA have advised that an in-vivo uptake factor (f 1 ) of 3.0E-05 should be used foralpha-rich beach finds containing 238 Pu, 239/240 Pu and 241 Am.• Beta-rich particles appear to have more diverse origins than alpha-rich particles withcontamination processes and creation directly from source material having a role.• The 137 Cs activity in beta-rich particles appears to be log normally distributed.• The age of beta-rich finds, based on their mean Caesium isotope ratios and aMagnox fuel origin, is greater than 16 years. It is not possible to tell if the beta-richfind ages are consistent with alpha-rich finds due to the limitations imposed on theage calculation by the limit of detection of the 134 Cs activity analysis.• count rate and dose rate monitoring data has been shown to be suitable foruse as an initial screening tool for all types of find.• On going work with respect to further analysis and assessment techniques will buildon what has been achieved to date with the main focus on expanding the use ofexisting and new data sources.3.3 Offshore MonitoringSeparate reports were produced in 2009 (Clough, 2009) and 2010 (Clough, 2010) to providean update on the efforts and progress being made towards offshore monitoring. Thesereports continue to be available via the sellafieldsites.com website. For 2011 the offshoreprogress update is being provided here as part of a joint report covering all particles in theenvironment work.3.3.1 Hydrodynamic Modelling ContractIn 2010, SL reported that a contract had been awarded to carry out higher resolutionmodelling of particle transport and dispersion off the Sellafield coastline. WestlakesScientific Consulting (WSC) was the successful contractor, supported by Cefas as subcontractor.Cefas had undertaken some initial particle modelling work under contract to theEnvironment Agency and this was to be developed further utilising the combined knowledge,experience and resources of WSC and Cefas. WSC had considerable experience in workingwith Sellafield Ltd, including the development and running of environmental models for theIrish Sea.The contract was set-up to deliver the following tasks (described further in the 2010 report):1. Analysis and interpretation of existing swath bathymetry data,2. Statistical analysis to optimise offshore monitoring design,3. Measurements of bed shear stress in the vicinity of the Sellafield discharge pipeline,4. 3D hydrodynamic modelling,5. Deliberate particle tracer release (evaluation) and6. Literature review of airborne transport of particles in the Cumbrian beach environment© Nuclear Decommissioning Authority 2011. 64

SSEM/2011/4730 June 2011Work commenced following a start-up meeting between SL and the contractors in February2010, with early focus concentrating on delivery of tasks 1, 3 & 6, with delivery of tasks 2, 4 &5 scheduled for later in the programme.Unfortunately and unexpectedly, WSC went out of business during the summer of 2010,resulting in the collapse of the hydrodynamic modelling contract, presenting SL with anumber of problems, both in relation to delivery of the above; and other work for the site thatwas reliant on the services of WSC.This contract had been in place for approximately six months when WSC went intoadministration, meaning that work had started on all of the tasks. At that time task 6 hadbeen completed by WSC; and tasks 1 & 3 were well underway with Cefas. Cefas had alsostarted some of the evaluation work to deliver task 5. Tasks 2 and 4 were to be deliveredthrough collaborative effort between WSC and Cefas and were in the early preparatorystages, being reliant on output from the other tasks to be completed.A major part of the work to improve the modelling was the gathering of new field data, inparticular the deployment of equipment onto the seabed to measure bed shear stress as partof task 3. In June 2010 an Aquadopp current profiler was deployed onto the seabed close tothe end of the existing sea pipeline diffusers. The plan was for a total deployment period ofapproximately six months. With a typical operating battery life lasting between 60 and 90days, the total deployment would be achieved by replacing the Aquadopp every 2 months(weather permitting). At the time of WSC folding, Cefas had the first Aquadopp in the watercollecting data and the timeframe for the first service/replacement visit was approaching.Without a contract in place there was a real risk that the Aquadopp work would not becompleted and a number of reports under preparation for other tasks would not be issued.The contract in place for the work was between SL and WSC; and due to the collaborativeelements of the contract, it was not legitimate on commercial grounds to re-award or transferthe remainder of the total contract directly to Cefas. However, the fact that equipment(Aquadopp and frame) had already been deployed and reports for other tasks were alreadybeing prepared by Cefas, meant that a limited contract was considered to be legitimate,allowing the ‘Cefas-only’ elements of the contract, that were already underway, to becompleted.Inevitably the need to prepare and issue a new contract did introduce delays for receipt offinal reports, against the original schedule, and has led to a re-think on the approach beingtaken for offshore monitoring. That said, the progress made against the completed tasks ofthe contract is reported below. Due to the collapse of the contract with WSC no progress isreported against tasks 2, 4 and 5. Discussion on the impacts of the failure to deliver thiswork can be found in Section 7.3 setting out the forward programme for offshorecharacterisation and monitoring.3.3.2 Progress on analysis and interpretation of existing swath bathymetry dataIn the 2010 update report, SL reported the initial findings from the Cefas analysis andinterpretation of the existing swath bathymetry data (see Figure 3.32), indicating that the datadid not fully satisfy the requirements of the transport and dispersion modelling work.In December 2010, Cefas were able to provide the finalised report on the swath bathymetrydata review; and provided the following conclusions:© Nuclear Decommissioning Authority 2011. 65

SSEM/2011/4730 June 2011[the Sellafield Ltd dive team vessel]Figure 3.32. Swath bathymetry along in the Cumbrian coastline within the Fledermaus 3Dvisualisation software. The position of the pipe (black line) and the navigation buoys (redcubes) are shown.SL accepts the Cefas conclusions and has been exploring options for obtaining an additionalswath bathymetry survey, including discussions with Environment Agency on use of theirsurveying capability. Further swath bathymetry survey work is discussed under Section 7.3.© Nuclear Decommissioning Authority 2011. 66

SSEM/2011/4730 June 2011A full copy of the Cefas report is provided to the Environment Agency as part of thesubmission package that accompanies this report.3.3.3 Progress on measurements of bed shear stress in the vicinity of the Sellafielddischarge pipelineA number of packages of work were included under this task, the major piece of work beingthe deployment of an Aquadopp current profiler. Other supporting packages included anevaluation of the feasibility to deploy Woodhead drifters and a review of historical currentmeter records.As reported in the 2010 report, Cefas were able to confirm that the required numbers ofWoodhead drifters were available and that a supplier had been identified to produce the tagsthat would provide details of what information would need to be returned by the finder of thedrifter. Unfortunately the collapse of the contract with WSC led to the decision not to pursuethe Woodhead drifter release at this stage. Whilst the release of the drifters is relativelystraightforward (released as a package by hand from a vessel at a recorded location) thefollow-up work of waiting for the drifters to come ashore and logging and interpreting theresulting data would have taken several months. The deployment of Woodhead drifters willremain an option for future consideration.Current meter data from the Sellafield pipeline (water depth approximately 15 mbelow chart datum), were recorded by Cefas (then MAFF) at various time periods betweenMay 1981 and March 1988. These data have been reviewed to help improve the descriptionof the hydrodynamics immediately off the Cumbrian coast at Sellafield, with the aim ofreducing uncertainty in numerical model predictions. Of particular interest are the indicationsof the direction of near bed currents during episodic events (e.g., storm waves, storm surge,and wind-driven currents) when the Sellafield-derived particles are most likely to be movingalong the sea floor.The current meter data were extracted from the Cefas data archive system and subjected toa data quality analysis. The currents were measured using Plessey M021 propeller-typecurrent meters (Figure 3.33). The direction is determined from an internal compass thatregisters the change in instrument heading as the current meter vane reorients to the flow.Current directions were corrected for magnetic declination. The data were originally stored inbinary form on magnetic tapes and have now been converted into computer data files.© Nuclear Decommissioning Authority 2011. 67

SSEM/2011/4730 June 2011Figure 3.33. Plessey M021 current meter. Source: NOAA (National Oceanic and AtmosphericAdministration) Photo Library and the Oceanographic Museum of Monaco. Photographer: Y. Berard.The review of historical meter data allows for comparison with the data gathered during theAquadopp deployment. This receives some discussion in the Aquadopp report produced byCefas, discussed further in the section below. Prior to the completion of the Aquadopp work,Cefas reported the following conclusions from the historical review.As previously discussed, an Aquadopp current profiler was deployed in the vicinity of the seapipeline end in June 2010. Deployment was achieved through collaboration with theSellafield Dive Team and Cefas. The Sellafield Dive Team operates the vessel Eagle thatwas used to deploy, service and recover the Aquadopp and its supporting frame (Figure3.34).© Nuclear Decommissioning Authority 2011. 68

SSEM/2011/4730 June 2011Figure 3.34. Aquadopp and landing frame being deployed from the Sellafield Ltd vessel, Eagle.The original proposal was for the Aquadopp to be deployed without the need for divers.However, on the first deployment visit the decision was taken to deploy divers in order toconfirm that the landing frame was in a stable and upright position on the seabed and toensure that all ropes etc were kept away from the Aquadopp, to avoid any snagging andthereby help maximise data gathering efficiency. Divers were deployed again during the firstservice/replacement visit to ensure safe delivery of the frame and Aquadopp back to thesurface. Divers were not deployed on all subsequent visits.The Aquadopp was scheduled for a deployment duration of approximately 6 months. Thecollapse of the WSC contract placed this in jeopardy, but the placing of a limited contract hasallowed for an extended deployment of approximately 8 months. This extension has meantthat data coverage captured conditions during the summer, autumn and winter months andhas included a number of notable storm-event periods.The final report on the analysis and interpretation of results was issued in June 2011 and willtherefore need to be considered further by SL before any decisions are taken on how thismay inform decisions on seabed monitoring. A full copy of the report is included as part ofthe submission package to the EA. For information the Executive Summary from the reportis copied below.© Nuclear Decommissioning Authority 2011. 69

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SSEM/2011/4730 June 20113.3.4 Progress on the literature review of airborne transport of particles in theCumbrian beach environmentBefore going into administration, WSC provided a report to SL on a review they hadundertaken on aeolian sediment transport. The review relates to a recommendation madeby Cefas who concluded that aeolian processes could be responsible for particle transportalong the beaches at and around Sellafield. Although not directly relevant to modellingoffshore particle transport and dispersion, aeolian transport is a potentially importanttransport mechanism.The WSC report collates available information on the Cumbrian beach environment andconsiders the nature of the radioactive particles that have been recovered in the context ofpublished work on sediment transport in beach environments and aeolian transport theory.An extract from the conclusions of the report are provided below.© Nuclear Decommissioning Authority 2011. 71

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SSEM/2011/4730 June 2011The potential for wind-blown transport and for very small radioactive particles to becomesuspended has been the subject of continued discussion and particle inhalation has beenconsidered by the Health Protection Agency in their risk assessment. Further discussions areto be held between SL, Environment Agency and the Health Protection Agency as part of apackage of supplementary work that HPA have been asked to do by the EA (discussedfurther in Section 5). During 2010 Nuvia began operating air sampling equipment duringparticle recovery operations on the beaches. This was introduced as a precautionarymeasure as part of the response to an investigation into the possibility for particle intake bybeach monitoring personnel (discussed further in Section 5). The results from the airsampling and the completed investigation show no evidence for airborne radioactive particlesor their inhalation. Air sampling during particle recovery operations has now become routine.3.4 Monitoring R&D: Evaluation of Airborne Gamma SpectrometryA key piece of ongoing R&D work that has continued through 2010/11 has been themodelling of gamma spectrometry systems, undertaken by the Scottish UniversitiesEnvironmental Research Centre. Previous modelling had indicated that the AirborneGamma Spectrometry (AGS) operated using helicopter, might be capable of detectingSellafield radioactive particles in the environment. This work has been further developedusing data from the Nuvia beach monitoring operations, in order to simulate detection ofSellafield particles on local beaches, taking account of the typical background activity levelsthat are observed.This work required an extension to the original contract. The issued report was submitted toSL in June 2011 and is included in the submission package to EA with this report. Forinformation, SL note the following extracts from the report. © Nuclear Decommissioning Authority 2011. 73

SSEM/2011/4730 June 2011The findings from this latest modelling work will need to be discussed with the EnvironmentAgency to determine any need for further work. Based on the reported detection capabilities;the need to post-process survey data; and the issues related to use of a low-flying helicopterover public beaches; the continued use of the Softrak Synergy system to achieve large areabeach monitoring, appears to remain justified.© Nuclear Decommissioning Authority 2011. 74

SSEM/2011/4730 June 20114. Regulator and Stakeholder engagementThroughout all aspects of the work described in this report, Sellafield Ltd seeks to maintainopen and honest communication with regulatory bodies and a wide range of otherstakeholders. The methods of communication are varied and include general updates andavailability of large amounts of information via the sellafieldsites.com website; through toattendance at specific meetings; and the production of detailed written documents (this reportfor example).The following provides further detail on the main processes for communication andengagement.4.1 General Engagement with the Environment AgencyThe Environment Agency specifies the following requirements on Sellafield Ltd for theparticles in the environment work scope:As part of managing the delivery of work against the above specification, Sellafield Ltd andthe Environment Agency communicate regularly via telephone, email, letter; and face-to-facemeeting on the full range of aspects associated with this work. Face-to-face meetings aretypically held at least quarterly throughout the year, providing an opportunity for generalupdates to be provided and for specific items to be discussed. Where a decision point isreached that requires agreement or approval by the Environment Agency, SL will make aformal written proposal before proceeding.© Nuclear Decommissioning Authority 2011. 75

SSEM/2011/4730 June 2011Communications and engagement with the Environment Agency is not limited to one-to-onedialogue. Where specific items require (or benefit from) wider discussion and input fromothers, separate meetings or Working Groups have been held or established (for examplethe Multi-Agency Workshop and Sellafield Seabed Monitoring Working Group, bothdescribed below).Sellafield Ltd is also required to prepare written submissions to the Environment Agency.This report forms the annual programme update submission that is referred to in the CEARspecification.Sellafield Ltd regards the need for effective and constructive communications with theEnvironment Agency on this complex subject as essential; and believes the processesemployed to achieve this, continue to be productive and ensure that good progress continuesto be made.4.2 Multi-Agency WorkshopIn November 2010 the Environment Agency hosted their third multi-agency workshop on thesubject of Sellafield radioactive particles in the environment. As with the previous workshopsSellafield Ltd delivered a number of presentations, providing updates on the work done todate and inviting discussion on the future direction and objectives for the work. In addition tothe material presented on the day, Sellafield Ltd also produced a paper in advance of theworkshop, providing background and further information to help facilitate discussions on theday. The workshop was attended by various government agencies and bodies (including theHealth Protection Agency; Food Standards Agency, and Committee on Medical Aspects ofRadioactivity in the Environment) and Local Authorities.This workshop forum provides an excellent opportunity for Sellafield Ltd to engage directlywith regulators and stakeholders; and SL will continue to support future workshops that areorganised.4.3 COMAREThe Committee on Medical Aspects in the Environment (COMARE) Sellafield Working Groupmet in February 2011 with a main focus on the particles in the environment work. TheEnvironment Agency provides a routine report summary to COMARE that details theprogress being made. The February meeting was only the second time that SL had beeninvited to attend the Sellafield Working Group. At the meeting, SL provided verbal updateson key issues of interest to the committee. The meeting was constructive, and provided anopportunity for SL to listen to and discuss some the committee’s questions first hand.4.4 Sellafield Seabed Monitoring Working GroupThe Seabed Monitoring Working Group has continued to meet through 2010/11 with a keymeeting held shortly after the November multi-agency workshop. In addition to the usualmembers of the Group from EA, HPA and FSA, the NDA attended this meeting to discussthe way forward for seabed monitoring. The main focus of the Group for 2010/11 hascontinued to be the risk assessment work that HPA and FSA have been conducting and thatwas issued in April 2011. Through 2011/12 SL will consult the Group on the development ofan offshore monitoring contract specification.© Nuclear Decommissioning Authority 2011. 76

SSEM/2011/4730 June 20114.5 Local stakeholdersSellafield Ltd has continued to communicate with local stakeholders on the work being done.This has included attendance and provision of information to various group meetings,including Parish Councils and the West Cumbria Sites Stakeholder Group; and responding toquestions raised by individuals. SL has also produced an information leaflet (see Figure 4.1)on the beach monitoring programme, copies of which are available to local residents andvisitors. An example of where Sellafield Ltd has responded to concerns expressed by localstakeholders is in the scheduling of beach monitoring to avoid the busy tourist times ofEaster and the summer school holidays for 2011/12.Figure 4.1. Information leaflet produced by SL to advise local residents and visitors on thebeach monitoring programme.© Nuclear Decommissioning Authority 2011. 77

SSEM/2011/4730 June 20115. Health Risk Assessment5.1 Health Protection Agency assessmentAs stated in the Introduction and Background sections of this report, quantifying the riskposed by radioactive particles is the main objective of this project. Since the start of theproject Sellafield Ltd have shared data with the EA and HPA to help meet this objective. Theformal advice given by the HPA in 2007 that, “no special precautionary actions are necessaryat this time regarding access to or use of these beaches”, has been reviewed and remainsvalid to date.In May 2008 the EA asked HPA to undertake an assessment of the health risks to peopleusing the beaches along the Cumbrian coast from contaminated objects on the beaches. Thereport was published in April 2011 and the Executive Summary is reproduced below: © Nuclear Decommissioning Authority 2011. 78

SSEM/2011/4730 June 2011 137 Cs 5.2 Uncertainty and recommendations for future workThe HPA report outlined the uncertainties associated with the risk assessment andrecommendations for how some these can be minimised (others are inherent to theapproach used, e.g. estimation of chance of encounter). Recommendations were also madefor ensuring that the current monitoring approach/programme is adequate.90 Sr is not directly detected using the Evolution 2 or Synergy systems, but rather as aresult of detection of 137 Cs. It is not clear whether there are significant numbers ofobjects on the beach that only contain 90 Sr or have low 137 Cs: 90 Sr ratios. It wasrecommended that further work is completed to determine, and if necessary improve,the 90 Sr detection capability of Synergy 2 (to activities greater than 400 kBq).The minimum detectable activity of the Synergy system corresponds to particles ofabout 300 μm. This raises the question about whether smaller particles remainundetected on the beaches with the potential to be inhaled. It was recommended thatenvironmental monitoring data (e.g. HVAS) should be reviewed to determine whetherthis is a potential exposure pathway.© Nuclear Decommissioning Authority 2011. 79

SSEM/2011/4730 June 2011The numbers of alpha-rich finds have increased since the introduction of the Synergysystem. This may be attributable to the improvements in detection sensitivity but thishas not been proven. If there are more alpha-rich finds present on the beaches thanpreviously thought, the risk assessment will need to be reviewed.Capabilities of the beach monitoring systems for detection of alpha-rich objects atdepth are limited by the physical nature of the detection process and the availabletechnology. These capabilities may not meet the requirements needed to ensuredetection of particles that could give rise to a significant risk to health if ingested. Iftechnical advances are made that would allow more reliable detection of alpha-richparticles at greater depths, these should be considered for implementation.For some beaches, particularly where the number of objects found is low, theuncertainties in the estimate of the actual number of objects present can be quitelarge. The accuracy of the risk assessment would be improved when more monitoringdata is available and if more accurate data were available on the depths of particlesdetected.These recommendations will be discussed by Sellafield Ltd, the EA and the HPA at ameeting in July 2011. Also, since this report was produced, HPA have been asked by the EAto update their assessment based on data collected since the introduction of the Synergymonitoring system in August 2009. A draft proposal has been produced for this work and thefindings are expected to be reported in 2011/12 financial year.5.3 Risks to workersThe HPA assessment focuses on health risks from radioactive objects to the public,accounting for both low probabilities of contact with objects and low levels of harm if contactwere to occur. Their report does not specifically address issues associated with workers whoobtain data and seek and recover radioactive objects from beaches. We have sought advicefrom a qualified Radiological Protection Advisor employed by Sellafield Ltd to providereassurance that adequate measures have been taken by Nuvia to protect its workers.5.3.1 Nuvia operationsUse of Groundhog Evolution2 and Synergy, and associated recovery methods, requiresspecific assessment of risk to Groundhog operators. Operations involve response to a ‘find’alarm in the Groundhog cabin and then use of handheld radiation instruments and tools toretrieve objects from the beach. Objects are transferred to sealed containers for transport toSellafield site for analysis.A number of the hazards identified in the HPA reports (Brown and Etherington, 2011; Oatway., 2011) apply for these operations, including potential for inhalation, ingestion, skincontact and wounds. These are commented on below, together with some of the associatedcontrols.Activity levels of particles are low enough not to cause significant external radiation tooperators and so this is not considered further as a significant protection issue. The HPAreport came to the same conclusion for the public. Of course, as part of compliance withtransport regulations, radiation measurements of containers are performed prior to transfer ofthe finds to Sellafield site.Inhalation, ingestion, and wounds are routes where radioactivity can deliver internal dose.The deliberate proximity of the operators to found objects negates the low probabilities© Nuclear Decommissioning Authority 2011. 80

SSEM/2011/4730 June 2011accounted in assessing risk for the public. Controls and measures are applied for thesespecific operations to ensure suitable protection of the operators. In that operations to findand retrieve objects are on public beaches, a dose level of significance for workers is takenas 1 mSv per annum, corresponding to a 5x10 -5 overall fatal risk (ICRP, 2007).5.3.2 InhalationOnce a find is located by the Groundhog systems, the operator needs to remove materialsurrounding the object. Often conditions are inclement, windy, not always wet, and so thereis potential for material, e.g. sand, to become airborne. Calculations on size of respirablematerial show that potential radioactivity associated with the particulate size is low (i.e.approximately 0.1 Bq of actinide activity) and presents little hazard unless large numbers ofparticles are inhaled. For example, the inhalation of approximately 375 particles of averagerespirable size is required to give a dose of 1 mSv. This is corroborated by the HPA’sevaluation in their reports (Randles, 2010).A proportion of the particle finds are known to be potentially friable (Randles, 2010). Theseconsist of aggregations of smaller particles that are stable when wet but prone to fragment asthey dry out, particularly when handled directly. The smaller particles will have a range ofsizes with a proportion of them being of respirable size.For an acute inhalation intake, analysing for worst case fraction of particles that becomefriable and worst case release fraction around the highest alpha-rich find, the calculatedpotential uptake to the operator is an order of magnitude below the significant dose. Even atthis low dose level, several thousand particles would need to be present to ensure there aresufficient respirable particles available for inhalation.For chronic inhalation uptake, analysis follows average activities, friability and releasefractions and results indicate that there is potential for uptake via this route that couldmarginally exceed 1 mSv per annum. This worse case assumption requires that most, if notall, particles are friable and their recovery generates sufficient respirable-size particles toallow a small number to be inhaled.However, natural mitigation is that beach materials are often wet and it is unlikely that themajority of finds dry out during recovery. Operational mitigation includes the requirement towet the material around a find zone, to reduce the risk of friability and therefore significantlyreduce the risk of chronic inhalation. An internal dosimetry regime for operators is also inplace to monitor this potential (and any ingestion potentials detailed below). Environmentalchronic inhalation uptake for operators is calculated to be more than 3 orders of magnitudeless than significant dose (Randles, 2010).5.3.3 IngestionWhereas the HPA reports recognise a potential (albeit very unlikely) for inadvertent orintended ingestion of radioactive objects by some categories of the public, operators do notfall into these person categories. Nevertheless, operators spend more time on the beachesthan members of the public (around 1200 h per annum). Calculations of sand intake byoperators, just by being on the beaches and looking for particles, show that there is potentialfor an attributable dose uptake but at 3 to 4 orders of magnitude less than significant dose.Given the qualified and experienced nature of operators as health physics surveyors, anacute ingestion intake is not credible. For example, for a 1 mSv acute ingestion dose it isimplausible that the 5000 Bq particle required would not be detected and for a 1 mSv chronicingestion dose it is implausible that the 150 ingestion events would take place. Operators© Nuclear Decommissioning Authority 2011. 81

SSEM/2011/4730 June 2011wear gloves during retrievals that are removed by correct practice after objects have beenretrieved. Operators do not put hand to mouth/face during retrievals while wearing gloves.The wetting process in retrieval prevents blown material that could be inadvertently ingested.5.3.4 Skin contact and woundsSkin dose is dependent on activity of an object and its time in contact or in close proximitywith the skin. Operators not only take precautions while retrieving objects but once a retrievalis complete (with objects sealed in containers), operators self check with contaminationmonitoring instruments to determine whether activity has become attached to their person,thus eliminating the potential for any prolonged contact should it occur. Consequently, thereis extremely low potential for skin dose during operations.Entry of material into the body via wound sites is a well recognised potential. Operators arewell versed in practices to seek and cover any wound site prior to working with radioactivematerials. In addition, use of gloves and standard work clothing mitigate against any intakevia wound sites.5.3.5 Reassurance by monitoring for internal uptakeEven though potential is low for intake and uptake of material into the body, a regime ofinternal dosimetry is provided for each operator. This involves monthly provision of sampleswith analysis on a quarterly basis but with stored samples for further analysis should anyuptake be suspected. For operations to date there has not been a dose uptake by anyoperator.5.3.6 Potential of exposure to the publicThe HPA reports cover the period of 3 years between the summers of 2006 and 2009. Sincethat time, Groundhog Synergy has been used, with its enhanced capability for detection ofalpha-rich objects. This has increased the number of alpha-rich finds, although the majorityof objects are of lower activity than previously seen (Synergy has greater sensitivity thanEvolution2). Thorough assessment of the effects on the public are the subject of furtherstudy but indicators are that finds are not so significant as to expect change in the overallcriteria for protection of the public that are described in the HPA reports.5.4 Nuvia dosimetry investigationIn the second half of 2010 Nuvia dosimetry bioassay (i.e. urine and faecal) samples from twoworkers engaged in beach monitoring exceeded the urine trigger level (0.2 mBq/day).Nuvia’s internal investigation concluded that a possible explanation for the results could bethe chronic ingestion of beach sand (with the most significant component being fromenvironmental levels rather than associated with find recovery), combined with thecontamination of urine samples with sand from the worker’s hands during sample provision(Randles, 2010).Sellafield Ltd asked the HPA to carry out an independent investigation to gain reassurancethat there was not a risk to the Nuvia workers. The report (Etherington , 2011) found thatthe possibility could not be ruled out that intakes giving rise to committed effective doses inexcess of 1 mSv could have occurred. However, they also found that the possibility could notbe ruled out that the bioassay results, in full or in part, could be explained by samplecontamination.© Nuclear Decommissioning Authority 2011. 82

SSEM/2011/4730 June 2011Following the HPA investigation, the final results of measurements on a urine sample thathad been collected after the sample upon which the Nuvia and HPA assessments werebased were reported. These results were not significantly different to that measured in asample provided by an un-exposed control subject, and were significantly lower than thebeach workers’ previous samples. Based on this information the HPA concluded that, basedon the information available, the most likely explanation for the elevated urine result wasinadvertent sample contamination (Etherington, 2011). This letter is available in full on ourwebsite.The HPA were also asked for their view on the effect of the Nuvia worker dosimetryassessment on the assessment of health risks to the public. HPA have written to SellafieldLtd to express their view, stating that,© Nuclear Decommissioning Authority 2011. 83

SSEM/2011/4730 June 20116. Aims and Objectives6.1 Introducing the requirement for large area beach monitoringThe 2008 Summary Report (Hemming, 2008) provides details on some of the backgroundand drivers that led to the introduction of a regulatory requirement for large area beachmonitoring at Sellafield. The report also sets out how the early programme for beachmonitoring developed.In brief, the detection, recovery and analysis of a particle containing 90 Sr, during routinemonitoring of the strandline on Sellafield beach in 2003, triggered a review of beachmonitoring operations. This review and subsequent trial of a vehicle mounted system in late2006 / early 2007 resulted in an evolving programme that has seen the development anddeployment of state-of-the-art detection equipment across a wide extent of the beaches onthe coast of West Cumbria.During the early programme, it was not known whether radioactive particles were present insignificant numbers and over what geographical range. Based on early modelling work, thefirst trials took place in areas where the highest chance of encounter had been predicted, tothe immediate north of the Sellafield site. As material was detected and recovered from thislocation; so the programme started to include beach areas that are more distant from theSellafield site. This has resulted in monitoring being carried out on sections of all the mainstretches of accessible beach along the West Cumbrian coast; and has included beaches onthe north Solway.Consistent with the aim of understanding the geographic range and distribution of particlenumbers, the specified area to be monitored increased as the programme developed. TheSellafield trial covered an area of 9.2 ha, followed by a 26 ha trial at Braystones (usingvehicle-mounted and hand-held equipment). The success of the trials led to the inclusion ofa specification in the Compilation of Environment Agency Requirements (CEAR) requiring “aminimum beach area of 15 ha …by 31 July 2007, with a minimum area of 100 ha to besurveyed by 31 March 2008”. In fact, the total area monitored during 2007/08 was in excessof 150 ha, against a revised specified area of 146.7 ha.Success in achieving what may be described as arbitrary target areas, effectively led to abeach monitoring programme of 250 ha per year. Year-on-year, the total area coverageactually achieved has exceeded the target, with last year’s coverage area totalling c.319 ha.These totals are corrected to take account of the overlap that is built into the vehiclemonitoring swathes to ensure that contiguous coverage is achieved. The specified area formonitoring has essentially evolved based on operational performance, as determined by therequired detection capability of the equipment; the natural constraints presented by work in abeach environment (beach accessibility, beach substrate, tidal window, available daylightetc); and the priority given to public protection and assurance. SL considers that 250 ha peryear represents the working capacity of the current system (Softrak running Synergy at1m/s), allowing for minimum down-time periods for vehicle maintenance and buffer time.6.2 Beach monitoring programme reviewThe early specification for Sellafield beach monitoring was heavily influenced by the workbeing done at Dounreay, where fragments of fuel are being detected in the environment. Asthe Sellafield programme has evolved it has become evident that the situation at Sellafield issufficiently different to that at Dounreay; and presents a number of unique challenges,including the types and relative distribution of contaminated material. As a consequence the© Nuclear Decommissioning Authority 2011. 84

SSEM/2011/4730 June 2011beach monitoring programme has been the subject of review each year, informed by therange of data being collected and analysed.For 2010/11 the Environment Agency revised the CEAR specification, in part to reflect thetransfer in programme management to SL. Rather than specify detection performance andthe target area to be monitored, the revised CEAR introduced the need for a targetedprogramme of works that is driven by risk and protection of the public.The 2010/11 beach monitoring programme was maintained at 250 ha and included periodsof investigative monitoring, both on beach areas that had not previously been monitored andon beaches that do not allow for vehicular access, where hand-held equipment would needto be deployed. Although the full programme was delivered by the end of the year, the2009/10 monitoring campaign did highlight a number of issues that would need to beconsidered when developing the 2011/12 programme. In particular, some local stakeholdershad asked that beach monitoring operations should avoid monitoring during peak touristperiods. In addition, achieving the investigative monitoring proved to be more demandingand resource intensive than planned, requiring weekend working and deployment ofadditional monitors.Through 2009/10 the HPA were developing their assessment of health risks from theradioactive particles detected and recovered from the beaches. Although only published inApril 2011, discussions with HPA in 2009 provided a clear indication that health risks werelikely to be very low (confirmed in the issued report as less than one in ten thousand million).SL has always tried to be responsive and pro-active in accommodating changes and newpriorities for the beach monitoring programme. During 2010, SL started to reconsider theprogramme against revised aims and objectives and developed a proposal for a return to 150ha per year. This proposal was put forward at the multi-agency workshop held in November2010; and later submitted in writing to the Environment Agency (see Appendix 5).6.3 Developing the approach for offshore monitoringThe presence of particles in the offshore environment remains an area of uncertainty, both interms of what material may be present and at what locations; and also how to monitor andretrieve it. In the absence of a proven system to execute sub-sea monitoring and particleretrieval at Sellafield, work to date has focussed on how to reduce the levels of uncertaintyso that sub-sea monitoring effort can be deployed in an efficient and effective manner.Whilst Dounreay have developed an ROV system for detection and recovery of 137 Csparticles, it is unlikely that this would be successful at finding the 241 Am particles present atSellafield. Monitoring on the seabed has the potential to cost many £Millions and thereforerequires thorough consideration to avoid nugatory expenditure in terms of effort and financialexpense.The main objective for 2010/11 was the further development of the offshore transport anddispersion modelling started by Cefas under contract to EA. This updated modelling workwas then to be used as the main input to the design and specification of an offshoremonitoring programme and delivery contract(s). Section 2.5 provides further detail on theprogress made during 2010/11 and the impact on this work caused by SL’s principlecontractor going out of business part way through the year.In brief, the collapse of the modelling contract has forced SL to re-think the approach tooffshore monitoring and to pursue a new contract model, whereby the design and executionof the monitoring programme would be awarded under a single contract. The scope and© Nuclear Decommissioning Authority 2011. 85

SSEM/2011/4730 June 2011specification for this new approach is being been informed by the work done and experiencegained to date.This new approach was discussed and agreed by the Sea-bed Working Group following themulti-agency workshop in November 2010. It was also agreed at the Sea-bed WorkingGroup that the scope of work should also be informed by the key questions that EA, HPAand FSA would requires answers to from offshore monitoring operations. Each Agency hassubsequently provided a question set to SL and these form a core component of the aimsand objectives that are described below.6.4 Developing aims and objectives for the particles in the environment workprogrammeThe paragraphs above provide a brief overview of some of the drivers for the work done todate to monitor beaches and the offshore environment. A significant amount of work hasbeen done to date and will continue over the coming years. Reflecting the amount of datagathered to date and what this is telling us about the risks associated with particles in theenvironment, SL has undertaken a review of the aims and objectives across all of theparticles work areas and has used the output from this review to determine priorities anddevelop an effective work programme.Included as part of this review are the views of stakeholders and specifically, the sub-seaquestion-sets provided by the EA, HPA and FSA:EA1. What are the risks to the public from exposure to radioactive particles via offshorepathways?2. Does the presence of particles offshore warrant any intervention measures to reducepublic risks to acceptable levels?3. Are there different particle types, or significantly more hazardous particles, offshore?4. What is the geographical nature and extent of particle contamination offshore?5. Could existing offshore particle populations change with time (will risks becomeunacceptable)?6. What is the relationship between offshore and onshore particle populations and theirgeographical extent?7. Are there any characteristics of offshore particles that would help to identify sourcesFSA1. Does the a) activity, b) frequency of finds or c) size of particles offshore differ from thedata collected on the beach?2. Where are the particles offshore moving to?HPA1. Is there potential for there to be a lot more contaminated objects on the beaches thanthere are now?2. Could there be an increase in higher activity objects on the beaches than have beenfound to date (could the intervention criteria be approached)?3. Is the object population on the beaches going to decrease with time or is thererepopulation such that the hazard remains for beach users?Rather than separate out the questions that need to be answered by beach monitoring andby offshore monitoring, SL has tried to consider questions that are applicable across all theparticles in the environment work. The format of the review was therefore a series of© Nuclear Decommissioning Authority 2011. 86

SSEM/2011/4730 June 2011brainstorming sessions where a full range of particle-related questions were captured andthen distilled into relevant groupings.The review also considered EA guidance on developing environmental monitoringprogrammes, identifying the following objectives that are relevant to particle monitoring:Assessment of doseAssessment of the effects on wildlifePublic & Stakeholder ReassuranceLong-term trendsDetection of abnormal / unauthorised releasesUnderstand / monitor behaviour of radionuclides in the environmentA matrix was generated that allowed cross-comparison of questions and objectives todetermine any overlap and identify those issues attracting the greatest numbers of questions.From this a set of overarching primary questions have been developed that are designed toaddress the full range of priority issues.© Nuclear Decommissioning Authority 2011. 87

SSEM/2011/4730 June 20116.5 Primary Questions and their GroupingThe following tables show the raw output from generating the questions matrix. It should beevident that each of the heading questions are being addressed by existing and future workstreams, as indicated by the “Key Workstreams” listed below each table. The sub-questionsrepresent the range of issues that each heading poses; noting that in some cases, answersto all of the sub-questions will not be necessary to resolve or satisfy the heading.1. What risk do the particles pose?1.1 Who is at risk?1.2 What are the exposure pathways?1.3 Is there a temporal change in the risk, both forward and back?1.4 What is the general (collective overall) population risk?What risk do the particles pose?1.5 Is there an ‘End Point’ determined by risk?1.6 What is the consequence if the risk is realised?1.7 What was/is/will be the maximum risk?1.8 Do we need to actively mitigate risk?1.9 What risks are perceived by the stakeholders?1.9.1 SL/NMP reputation?1.9.2 Non-dosimetric risks?1.9.3 Business risks?1.10 Can we reliably model the transportation and dispersion of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeParticle Analysis ContractHPA risk assessmentFSA risk assessment© Nuclear Decommissioning Authority 2011. 88

SSEM/2011/4730 June 20112. What is / are the source(s)?2.1 Determine how many potential sources of particles there are2.1.1 From which plants and processes do they come & when did such discharges occur?2.1.2 Were they historic discharges from abnormal events?2.1.3 Were they historic routine discharges from the days prior to filtration?2.1.4 How do pebbles & stones behave to long term activity exposure (e.g. in old sections of pipeline)2.1.4.1 What is the maximum activity a pebble or stone can absorb/adsorb?2.1.4.2 Can this maximum be reached while using the current discharge system?What is / are the source(s)?2.1.5 How does sand and rusty metal behave to long term activity exposure (e.g. in old sections ofpipeline)?2.1.5.1 What is the maximum activity a sand or rust particle can absorb/adsorb?2.1.5.2 Can this maximum be reached while using the current discharge system?2.2 Consider the 1983 Beach Incident discharge:2.2.1 What was discharged?2.2.2 Is there a modern analogue that can be analysed?2.2.3 In 1983 why didn’t we see anything like we can see today, resulting from this discharge?2.3 Consider the Pipeline recovery work of the late 1990s and 2003:2.3.1 Can we acquire and sample a piece of recovered pipeline from LLWR?2.3.2 Can we determine from those involved in the pipeline recovery project what the condition of thepipeline was?2.4 Can we reliably model the sources of particles?Key Workstreams:SL Particles Sources and Pathways Working GroupBeach Monitoring ProgrammeParticle Analysis Contract© Nuclear Decommissioning Authority 2011. 89

SSEM/2011/4730 June 20113. Where are the particles (ie distribution along the coast and seabed)?Where are the particles (ie distribution along the coastand seabed)?3.1 What technology is available to allow us to map / detect subsea particles?3.2 What limitations are there on the ‘effective’ use of that technology?3.3 Over what area do we look for particles and where do we start and finish?3.3.1 Where are we most confident that we will find particles?3.4 What do we need to allow us to model the technology / capability?3.4.1 What are the success criteria?3.5 What hierarchy of criteria do we adopt when choosing the technology?3.6 Can we reliably model the distribution of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeStatistical Analysis Contract© Nuclear Decommissioning Authority 2011. 90

SSEM/2011/4730 June 20114. How many particles are there?4.1 Can we calculate the number of particles in terms of:4.1.1 Total particle number?4.1.2 Sub population numbers?4.2 Can we estimate from beach ‘finds’ what the total numbers of particles are?How many particles are there?4.2.1 Define the population of stones, i.e. what was found, where it was found and when it was found?4.2.2 Are we looking in the right place(s) for particles (sand/shingle/cobbles)?4.2.3 Are there sub populations of particles and how do their spatial distributions vary?4.3 How many particles are available for detection at any given time?4.3.1 How many are mobile?4.3.2 What is the repopulation rate?4.3.3 Are there ‘non-natural’ means by which particles are moved/redistributed in the environment, suchas by Trawlers or Dredgers?4.4 Can we reliably model the numbers of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeStatistical Analysis Contract© Nuclear Decommissioning Authority 2011. 91

SSEM/2011/4730 June 20115. What is the activity distribution of the particles population?What is the activity distribution of the particles population?5.1 What are the key radionuclides and how many particles of each type are there?5.2 What LOD do we need to achieve?5.3 How many particles do we need to analyse by:5.3.1 Coarse screening?5.3.2 Detailed analysis?5.4 What does the activity of ‘Finds’ tell us about the distribution of the ‘True’ populations?5.5 Is there a temporal change in the activity distribution (including spatial – Q3)?5.6 Does any temporal change tell us about the source term (refer to Q2) or ultimate environmental fate?5.7 Can we reliably model the activity distribution of the particles population?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeStatistical Analysis Contract6. Where are the particles going?6.1 Are they moving into high risk areas such as Mussel beds?Where are the particles going?6.2 Over what time-frame do particles move from their ‘original’ location (both on and off-shore) to their‘current’ location?6.3 Are we observing re-population between on-shore and off-shore particles or does location remainstatic (i.e. covered to uncovered at the same location)?6.4 How long do they remain as ‘particles’ in the environment?6.5 What is the maximum distance an independent particle can travel in the marine environment off theWest Cumbrian coast?6.6 Can we reliably model the transportation and dispersion of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeStatistical Analysis Contract© Nuclear Decommissioning Authority 2011. 92

SSEM/2011/4730 June 20117. What are the physical and chemical properties of the particles?What are the physical and chemical properties ofthe particles?7.1 What do we need to know about the physical and chemical properties to support:7.1.1 Categorisation?7.1.2 Source term identification?7.1.3 Modelling?7.1.4 Risk (i.e. dose factors)?7.1.5 BPM for particle detection?7.2 Can we reliably model the properties of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeParticle Analysis Contract8. How long have the particles been in the environment?How long have the particles been in theenvironment?8.1 How long have particles been available for transportation in the environment (i.e. may have beensitting static in the pipeline for an unknown period of time)?8.2 How does time in the environment affect the physical & chemical properties of particles?8.3 What is the diversity of environmental conditions (buried/surface/storm transport/tidaltransport/mud/silt/sand/boulder/pebble)? How does time spent in different conditions influenceparticle behaviour over time?8.4 What age of particles would be considered to originate from ‘current’ operations?8.5 What information is available on when pipeline cutting/removal has taken place, diffusers replaced orwhen environmental release events have occurred, that may assist in making modelling assumptionson ‘origins’ of releases?8.6 Have particles that have travelled the furthest been in the environment the longest?8.7 Can we reliably model the transportation and dispersion of particles?Key Workstreams:Beach Monitoring ProgrammeOffshore Monitoring ProgrammeParticle Analysis ContractStatistical Analysis Contract© Nuclear Decommissioning Authority 2011. 93

SSEM/2011/4730 June 2011Fundamentally, the priority question is “What risk do the particles pose?” with all otherquestions becoming academic if the risks are demonstrably low enough to be regarded asacceptable. The HPA risk assessment provides strong demonstration that the risks to beachusers are very low (one in a hundred thousand million of a fatal cancer), but that some beachmonitoring should continue in order to provide reassurance that risks remain very low.Based on the available information, the risk from offshore particles is also considered to below and regarded as acceptable by the FSA.The programme of work for particles in the environment could therefore now be regarded asa programme of reassurance, the scope of which is driven by the ability to demonstrate thatrisks continue to be acceptable. In order to achieve this and address the questions set-outabove, the programme for 2011/12 has the following main objectives:Beach Monitoring- to complete a programme of large area beach monitoring using the Nuvia Synergy systemthat achieves:- monthly monitoring (at least 10 times per year) at Sellafield beach;- monitoring of the full extent of the strand-line between St Bees andRavenglass:- monitoring at local beaches with the highest public occupancy for riskreassurance;- repeat area monitoring to understand repopulation at the following beaches:i. Sellafieldii. Braystonesiii. Seascaleiv. St Bees- recovery of all particles detected;and:- avoids as far as possible, monitoring during the peak tourist seasons.Find Analysis- to deposit all finds in the SL laboratory for gamma scan;- to complete the Tranche 3 detailed analysis by October 2011 (Serco/NPL)Data Analysis and interpretation- to continue populating the GIS system with data on the position and type of all finds;- to investigate and review the sources and pathways of beta-rich finds;- to interrogate beach monitoring data to determine find arrival / repopulation rates; and- to investigate application of statistical techniques and engage statistics experts to furtherevaluate beach monitoring data.Offshore Monitoring- to investigate options for the trial of the Dounreay ROV;- to support EA in achieving sampling of offshore sediments;- to develop the scope and specification for award of an offshore monitoring contract (seeexample Task Sheet, Figure 7.3)Risk Assessment- to provide data to HPA for their review of the risk assessment, to account for developmentsfollowing the introduction of Groundhog Synergy; and- to review the findings of the risk assessment to inform the particles in the environmentprogramme of work© Nuclear Decommissioning Authority 2011. 94

SSEM/2011/4730 June 20117. Programme of work for 2011/127.1 2011/12 Beach Monitoring ProgrammeThe programme for 2011/12 was developed by Sellafield Ltd and agreed with the EA prior toits commencement. As in previous years this programme is set to run from the start of Aprilto the end of March, consistent with the financial year. A programme of 150 ha was proposedas being the most appropriate for the following reasons:Using one monitoring vehicle, such as the Soft-track, the maximum area that can berealistically achieved in a year is 150 ha when taking into account the two periods ofno monitoring (during the Easter and Summer school holidays), the constraints oftides and allowing time to conduct walked strandlines and occasionalvehicle/equipment maintenance. In order to monitor a larger area an additionalvehicle would have to be operated which would significantly increase the cost ofbeach monitoring.Based on the information available to date the HPA risk assessment concluded thatThis assessment was based on an understanding of the spatial distributionof finds, the activity distribution of finds and their physical and chemical propertiesgained from the five years of large area beach area monitoring completed bySellafield Ltd. The ongoing aim of the programme is to provide reassurance that theoverall risks to beach users are not significantly greater than those estimated in theHPA assessment. This aim can be achieved with a more targeted programme thatfocuses on beaches with the highest find rates and public occupancy.An area of uncertainty in the HPA risk assessment is the nature and abundance ofany radioactive finds that may be present on the sea bed. Our focus has turned tooffshore investigations, including collecting samples from the seabed for analysis andmodelling of currents and particle movements to help reduce this uncertainty. Thiswork represents a significant financial commitment (see Section 7.5 for details) thatcan, at least in part, be met by reducing the cost of beach monitoring.The basis for a 150 ha programme was outlined at the multi-agency workshop hosted by theEnvironment Agency in November 2010. No significant objections were made by members atthe meeting. The programme was slightly revised to take into consideration the points raisedat the workshop and submitted to the EA in February 2011 (Appendix 5). Additionalinformation to support the programme was sent to the EA in advance of a meeting withCOMARE in March 2011 (Appendix 5). The key aspects and justification of the 150programme are:The 150 ha programme includes monthly visits to Sellafield beach, and regular repeatvisits to Braystones, St Bees and Seascale. These repeat visits facilitate the ongoingremoval of finds from these areas of beach and provides useful information on findnumbers over time. The beaches selected specifically for repeat monitoring havebeen identified based on a number of criteria: i) high find rates, ii) high levels of publicoccupancy, iii) extensive historic monitoring data, iv) consistent sand coverage, v)high confidence of monitoring repeatability.For each of these beaches, specified repeat area boxes have been identified. AtSellafield beach 2 areas (boxes) have been selected. These are both 1 hectare in© Nuclear Decommissioning Authority 2011. 95

SSEM/2011/4730 June 2011size and will be re-monitored eleven times each during the programme year.Selection of these areas has focussed on beach areas for which data has beencollected in previous years monitoring (Table 7.1) and where consistently high findrates have been observed. These boxes represent the core area to be covered oneach and every visit to the Sellafield beach, with additional coverage of theneighbouring beach, up to a total of 4 hectares dependent on available area at eachmonitoring visit. This combination of core areas and additional area affords a degreeof flexibility in the monitoring and avoids overly constraining the contractor in what arechallenging working conditions.Likewise, at Braystones 2 box areas have been selected. These are larger in size (5hectares) and will be revisited three times in the programme year. As with Sellafield,each of these areas has been revisited extensively in previous years monitoring; andrepresent areas of elevated find rates. A total of 14 hectares will be covered on eachvisit to Braystones, to include both of the defined 5 hectare boxes.Both St Bees and Seascale are beaches that are regularly visited by members of thepublic. At each beach a single area (3 hectares) has been selected, closest to themain parking areas and public access points. St Bees will be revisited five timesduring the programme year, with Seascale revisited three times, reflecting thenortherly bias to find rates. The visits to these beaches have been scheduled closelyaround the Easter and Summer breaks, during which the highest occupancy levelsare expected. A total area of 24 hectares will be covered at St Bees, with a total of 14hectares covered at Seascale.In the context of the total monitoring, repeat areas represent approximately 50% ofthe 150 hectare programme. Details of the repeat monitoring areas are summarisedbelow and accompanying maps can be found in Figure 7.2Table 7.1. Repeat areas for the 2011/12 beach monitoring programmeRepeat box Area (ha)Number of previous monitoringvisits*Sellafield 1 (north) 1 9Sellafield 2 (south)** 1 10Braystones 1 (north) 5 9Braystones 2 (south) 5 10Seascale 3 5St Bees 3 6*Based on complete or part coverage of the repeat box.**The 1 ha had to be split into two boxes to avoid a small area of large rocks.Braystones beach, with its relatively high find-rates and greater public occupancylevels than Sellafield, will continue to dominate as the beach with the largest targetmonitoring area. As in previous years, monitoring will take place a number of times.The requirement for a walked wind-blown strandline monitoring has also beenincorporated into the programme at appropriate quarterly intervals. This monitoring,which normally takes about three days to complete, has been identified alongside theneed for regular vehicle maintenance.Blocks of “buffer time” when no monitoring will be completed. In previousprogrammes, week-long blocks have been incorporated to allow for recovery of theprogramme in the event that unforeseen circumstances (e.g. inclement weather or© Nuclear Decommissioning Authority 2011. 96

SSEM/2011/4730 June 2011technical complications) impact on the ability of the contractor to achieve beach targetareas in any given monitoring block. This year, in response to concerns raised bylocal stakeholders about possible detrimental aspects of beach monitoring operationsduring peak tourist seasons, no monitoring is planned during the Easter (4 weeks)and Summer (6 weeks) school holidays. Where monitoring is required during thebuffer time, all efforts will be made to avoid those beaches with the highest publicoccupancy. Recognising the long summer buffer period, beaches with the highestpublic occupancy rates (St Bees and Seascale) are scheduled to be monitored asclose as possible to the start and finish of this break. This should mean thatmonitoring takes place at times that are most representative of periods when thebeaches have their highest occupancy, but without the adverse impacts of monitoringwhen large numbers of the public are present.As a result of introducing these repeat visits either side of the buffer periods and bybreaking the majority of monitoring periods down into week-long blocks at eachbeach, the number of monitoring visits to St Bees and Seascale will be increasedcompared to the 2010/11 programme.For 2011/12 we are including beach areas from last years’ investigations as namedbeach areas in the programme (Allonby, Whitehaven North and Harrington), togetherwith a non-beach specified Investigation period. The specific inclusion of Allonby,Whitehaven North and Harrington, recognises the interest in continued monitoring onbeach areas to the north of St Bees where a small number of finds have beenrecovered on some of the previous visits. A decision on how best to allocate theInvestigation period will be made closer to the time. Sellafield Ltd will consult with theEA on this allocation.To the south of Sellafield, beach monitoring has been carried out at Drigg beach eachyear, extending to Drigg Point and the Ravenglass estuary. The HPA presentation tothe multi-agency workshop in November 2010 included a recommendation for:. Consistent with this recommendation, Driggbeach will be monitored twice during 2011/12.We believe the programme is commensurate with the levels of risk as currently assessedand is capable of providing reassurance that risks remain very low. The programme fits withthe HPA’s advice for, (Cooper, 2011). As in previous years, where findings from themonitoring result in the need to review the programme, this will be done in full consultationwith the EA.Week StartingSoftrak Beach MonitoringAreaTargets (ha)4 Apr Sellafield (a) 411 Apr18 Apr25 AprBuffer Time –2 May9 May Sellafield (b) 416 May St Bees (1) 423 May Vehicle Maintenance/Strandline© Nuclear Decommissioning Authority 2011. 97

SSEM/2011/4730 June 201130 May Drigg (1) 506 Jun Sellafield (c) 413 Jun20 JunBraystones (1) 1427 Jun4 Jul Sellafield (d) 411 Jul Seascale (1) 518 Jul St Bees (2) 425 Jul1 Aug08 Aug15 AugBuffer Time –22 Aug29 Aug5 Sep Sellafield (e) 412 Sep St Bees (3) 419 Sep Vehicle Maintenance/Strandline26 Sep Seascale (2) 53 Oct Sellafield (f) 410 Oct Whitehaven North/Harrington 417 Oct24 Oct30 OctBraystones (2) 187 Nov14 Nov Sellafield (g) 421 Nov Whitehaven North/Harrington 428 Nov St Bees (4) 45 Dec Sellafield (h) 412 Dec Allonby 419 Dec Vehicle Maintenance/Strandline –26 Dec Christmas Break2 Jan9 JanSt Bees (5) 816 Jan Sellafield (i) 323 Jan Investigation 430 Jan6 FebBraystones (3) 1413 Feb20 Feb Sellafield (j) 327 Feb Seascale (3) 45 Mar Drigg (2) 412 Mar Sellafield (k) 319 Mar Vehicle Maintenance/Strandline –26 Mar Buffer TimeCumulative Totals ==>150 ha© Nuclear Decommissioning Authority 2011. 98

SSEM/2011/4730 June 2011Beach Number of visits Hectare CoverageSellafield 11 41Braystones 3 46St Bees 5 24Seascale 3 14Investigation 1 4Drigg 2 9Whitehaven/Harrington 1 8Allonby 1 4Total 27 150Figure 7.1. 2011/12 Beach Monitoring Programme© Nuclear Decommissioning Authority 2011. 99

SSEM/2011/4730 June 2011Figure 7.2. St Bees beach repeat area for 2011/12.© Nuclear Decommissioning Authority 2011. 100

SSEM/2011/4730 June 2011Figure 7.3. Braystones beach repeat areas for 2011/12.© Nuclear Decommissioning Authority 2011. 101

SSEM/2011/4730 June 2011Figure 7.4. Sellafield beach repeat areas for 2011/12.© Nuclear Decommissioning Authority 2011. 102

SSEM/2011/4730 June 2011Figure 7.5. Seascale beach repeat area for 2011/12© Nuclear Decommissioning Authority 2011. 103

SSEM/2011/4730 June 20117.2 Application of BAT for beach monitoring7.2.1 IntroductionSellafield Ltd is required to ensure that best practice is used to meet the objectives of beachmonitoring. This has been specified in the CEAR for paragraph 19 schedule 1 of theAuthorisation since the start of the large area programme. The current wording is below: Since the commencement of large area beach monitoring several pieces of work have beenundertaken to ensure the application of best practice. In 2008 Serco were awarded acontract to investigate the BPM options for beach monitoring. The work involved a deskstudy, technical workshop and a BPM study (Serco/TAS/2301/002). Using the Serco studyas a basis, the BPM approach was determined by Sellafield Ltd at the start of 2009(Desmond, 2009). The Serco reports and the BPM determination were peer reviewed byEntec on behalf of the EA. Progress against recommendations from BPM determination weremade in March 2010 (Dalton, 2010a), a review of techniques by Serco in September 2010(Locke, 2010) and an updated BPM determination was completed in March 2011 (Dalton,2010b). Another review of techniques is scheduled for October 2011.7.2.2 Beach monitoring detection equipmentFor the latest BPM determination, information on the technical development and utilisation ofthese techniques has been gathered by web-searches, examination of manufacturer’sinformation and by personal contact with other experts in the field. The basic information foreach technique has been updated and the Ministry of Defence Technology Readiness Levelscale has been used to assess whether or not the technique has advanced sufficiently to beconsidered for this application. For those new techniques which showed the most promise acomparison was made against the current beach monitoring best practice. The BPMelements considered were:Monitoring technologyEase of useManagement control and monitoring operationEquipment maintenanceRecord making and retentionAwareness and trainingRSA93 complianceCostSince the 2008 BPM review Nuvia Ltd has implemented their new Synergy monitoringsystem (in August 2009), which has incorporated eight thin NaI crystal FIDLER (FieldInstrument for the Detection of Low Energy Radiation) detectors along with an array of five© Nuclear Decommissioning Authority 2011. 104

SSEM/2011/4730 June 2011large volume NaI detectors. This has enabled not only the practical examination of detectionof alpha sources by X-ray and low energy gamma emission but also the examination of thedetection of Bremsstrahlung for beta sources, which was identified as ‘potentially useful inthe future’ in the 2008 study.While technical progress is evident for two of the other techniques, large inorganicscintillation detectors and large volume High Purity Germanium (HPGe) detectors, this isinsufficient to recommend immediate implementation. It is, however, recommended that atechnology watch is maintained for these techniques as more information may emerge thatwould enable their benefits to be more clearly defined.The practical implementation of FIDLER detectors has provided a reasonable proof ofprinciple for the detection of alpha emitters using X-ray and low energy gamma radiationusing thin crystal HPGe. However, there is insufficient evidence of the performance of thinHPGe detectors to indicate that this method would provide a significant advance inperformance over the FIDLER detection system. It is recommended that the technologywatch be maintained for the thin crystal HPGe technology. These recommendations aresummarised in Table 7.2.For the other techniques reviewed there has either been insufficient technical developmentover the last two years or further analysis has indicated that it is unlikely that they will besuitable for this application within the next 5 years. It is recommended that these are notconsidered further.The conclusion of the BPM review of the potential beach monitoring techniques is that noneare at the level of the current best practice system based on Nuvia's Groundhog TM Synergysystem. The current Groundhog TM Synergy system meets the current beach monitoringobjectives and is expected to do so for the foreseeable future.Table 7.2. Recommendations from BPM assessment.Recommendation Timescale Report Date1. Maintain a technology watch oninorganic detector development withrespect to possible use for large areabeach monitoring.2. Maintain a technology watch on ModularHPGe and thin crystal HPGe detectordevelopment with respect to possibleuse for large area beach monitoring.3. Maintain a technology watch onemerging technology that may providedetector systems suitable for large areabeach monitoring.4. Employ the MOD's technology readinesslevel procedures to judge the abovebeach monitoring technology watch andfor future BPM reports.October 2010 – November2012October 2010 – November2012October 2010 – November2012N/AMarch 2013March 2013March 2013N/A© Nuclear Decommissioning Authority 2011. 105

SSEM/2011/4730 June 20117.2.3 Consistent approach for statistical interpretationRecent work has been commissioned by Sellafield Ltd to review statistical techniques thatcan be used to help define the beach monitoring programme (described in Section 3.2). Thiswork has stressed the need to control and account for any changes to the measurementmethods, sampling protocol and laboratory procedures in order to successfully interpret thedata. Therefore, any potential improvements to the current system or development of anynew systems will need to be judged against the impact on statistical interpretation of the datacollected to date.7.2.4 Monitoring speedThe Hillcat and Soft-track vehicles have been driven at 1 m/s (2.2 mph) since the large areabeach monitoring programme began in 2006. This speed was originally chosen for Dounreaybeach monitoring because it is able to achieve acceptable Limits of Detection using theSodium Iodide detectors; it was adopted for the Sellafield programme rather then beingspecifically developed. Travelling at higher speeds (e.g. 2 m/s) will enable greater areas ofbeach to be covered, albeit with increased Limits of Detection, effectively reducing the depthof sand that is being monitored. Depending on the relative changes in area and depth ofsand monitored, the vehicle speed could be optimised to maximise the volume monitored.This may more effectively achieve the current set of objectives for beach monitoring, forexample, by allowing a greater area of reassurance monitoring to take place whilstcontinuing to recover the higher activity finds from the beach.Initial discussions with the contractor (Nuvia) have suggested that, apart from on smallpatches of sand, speeds above 1 m/s would be possible. Full details of the LODs achievablefor 137 Cs, 60 Co, 241 Am, 90 Sr/Y at 1.0, 1.5 and 2.0 m/s were given in Nuvia’s original tender forthe beach monitoring contract. Broadly speaking, increasing the speed to 1.5 m/s increasesthe LOD by a factor of ~1.3 and increasing the to 2.0 m/s increases the LOD by a factor of~1.8. It may be possible to improve these LODs by increasing the sampling rate.Whether increasing the monitoring speed represents best practice will be considered whenthe 2012/13 programme is being developed.7.2.5 Daily overlap of monitoring areaThe current monitoring procedure involves overlapping the previous Soft-track detectorswathe by the width of the caterpillar track. Overlapping is necessary to ensure 100%coverage of the area at the specified LODs because the detectors will be “off-axis” at theedge of each swathe. Unlike the Dounreay programme, where 100% coverage of specificbeaches is required by SEPA, the Sellafield programme considers much larger areas ofbeach and is not required to guarantee complete coverage. The overlap is approximately 30cm wide and represents about 15% of the total area covered during each survey. Avoidingany overlap has the potential to increase the monitored area by up to 15% without increasingthe duration of the survey or cost. It is worth noting that under the current practice there is nooverlap on narrow parts of the surveys that are only one track wide, at the edge of anysurvey area and at vehicle turning points.As part of the ongoing review of BAT we will be reviewing how many finds have beendetected in previous overlaps and whether their activity is significant or not.© Nuclear Decommissioning Authority 2011. 106

SSEM/2011/4730 June 20117.2.6 Strandline monitoringMonitoring of both the most recent tide-line (referred to as the Strandline) and the line ofwind-blown debris or highest tide-line (referred to as the Stormline) has been part of thewider environmental monitoring programme since 1983. Since 2009 Nuvia have beencarrying out annual strandline surveys using the vehicle-mounted Evolution 2/Synergysystem and quarterly walked stormline surveys using the Evolution 2 system. This monitoringis complimented by quarterly walked surveys by Sellafield Ltd, using a SLR GM forbeta/gamma detection and FIDLER probe for low energy photons.There have only been 8 stones found on the strandline and all but one have all been onSellafield beach with one on Braystones beach. As well as a low find rate, conductingstrandline surveys is particularly time-consuming and comparatively more expensive thanmonitoring open areas of beach. The hand-held equipment is also less sensitive than thevehicle mounted detectors.As part of the BAT case for Sellafield Ltd’s environmental monitoring programme beingdeveloped in 2011/12, the value of this monitoring will be assessed against the programme’sobjectives.7.2.7 Alternative monitoring methodsIn addition to optimising methods for monitoring the beach using vehicle-mounted detectors,the potential for helicopter-mounted detectors to meet the monitoring objectives has beenconsidered. Detailed modelling of its potential has been completed (see Appendix 4).7.3 Offshore Monitoring for 2011/127.3.1 Continued dialogue with Dounreay Site Restoration LtdThroughout the particles work at Sellafield, dialogue has been maintained with Dounreay SiteRestoration Ltd (DSRL) to understand the progress being made there. The current DSRLoffshore monitoring contract is with Land & Marine, with Nuvia as a sub-contractor. Land &Marine completed their first season of offshore monitoring in the Autumn of 2010, exceedingthe target area and taking advantage of good weather to extend the monitoring season andaccelerate work originally planned for 2011. The good progress made in 2010 means thatDSRL are on track to complete the total offshore area of 60 ha within the planned 3 yearcontract period. If good progress is made against the target area for 2011, DSRL may againopt to accelerate work and extend Land & Marines target area to achieve coverage that iscurrently scheduled for 2012.The good progress being made by Land & Marine at Dounreay has prompted SL to againexplore whether the opportunity exists to trial the ROV system at Sellafield. The NDA hasinvested heavily in the work being done at Dounreay and a trial would establish whether thebenefits from this investment could be maximised by effective deployment at Sellafield. Thatsaid, it should be stressed that the Dounreay ROV system, PRVII, has been developed fordetection and recovery of fuel particles with high concentrations of 137 Cs; and not for thetypes of alpha-rich material that SL are recovering from the beaches around Sellafield. It isrecognised that the current detection system is unlikely to deliver the long-term solution tooffshore monitoring at Sellafield and any trial would only be able to deliver a partialdemonstration of capability.© Nuclear Decommissioning Authority 2011. 107

SSEM/2011/4730 June 20117.3.2 DSRL ROV TrialTo explore the possibility for a trial deployment of PRVII, Sellafield Ltd have been activelyinvolved in a series of meetings with DSRL, Land and Marine and Nuvia to discuss thefeasibility and potential scope for an offshore monitoring trial at Sellafield. Early discussionson feasibility were positive with Land & Marine and Nuvia confident that a trial would yielduseful information on current seabed conditions and the presence of particles. Discussionsalso indicated that there was an opportunity for the trial to take place in late summer/earlyautumn of 2011. This timeframe was suggested to take advantage of the fact that the Land &Marine vessel would need to pass Sellafield on its return leg to Bromborough on the Wirral.Trial deployment as part of this return leg would reduce the charges for mobilisation and demobilisation.In discussing costs for the trial an early estimate of £300k-£400k wassuggested for a 2 week visit during return to the Wirral.Having established that a trial deployment should be technically feasible, discussion turnedto understanding the commercial and contract implications and whether suitablearrangements could be put in place to meet the 2011 timescales. It was apparent from thesediscussions that there are a number of issues that present sufficient commercial andcontractual risk that a successful trial in 2011 could not be guaranteed and would thereforenot be pursued further. The opportunity for a trial in the future has not been ruled out by SL;and progress at Dounreay will continue to be monitored. At the time of writing, Land & Marineare close to completing the target area of 16.5 ha for 2011. The potential for a future trial ofthe DSRL ROV remains an option in the forward programme.7.3.3 EA Grab SamplingIn parallel to the evaluation of an ROV trial, Sellafield Ltd has also been in discussion withthe EA to carry out some limited “grab” sampling of the seabed during the summer of 2011.The detailed specification for this work is still being developed and the work will be run as anEA led project, but it is hoped that samples will provide useful information on seabed activitylevels as well as an indicator of particle populations. The project will utilise an EA vessel andsampling resources with Nuvia providing on-board monitoring and sampling of recoveredsediments.SL is supportive of this work and has been involved in establishing the outline proposal andfacilitating discussions between the EA and Nuvia. The proposal involves using a mechanicalgrab to collect sediment from the seabed. The sample is subsequently raised onto the deckinto monitoring trays before a health physics survey is carried out. A number of bulk sampleswill be retained for further on-shore analysis including Am/Pu, Cs and particle size.In consultation with the EA, Sellafield has generated a map that identifies a triangular targetarea for grab sampling. The target area has been defined based on the length of beach thathas continued to see the highest concentration of beach finds recovered since the start of themonitoring/retrieval programme and the position sea pipelines and diffusers (Figure 7.5).Details of the specific location of samples will be defined prior to the sampling exercise.However, the EA have indicated that a significant proportion of samples will focus on the seapipeline discharge outfall. It has been suggested that additional grab samples are taken atregular intervals (e.g. on a systematic grid) to provide further information on backgroundsediment activity levels along the coast. The grab sampling work will be short in duration andconsequently the scope for wider area sampling may not be achievable.In early discussions with the EA, the opportunity was discussed for this work to be expandedto include collection of a broader range of survey information, including swath bathymetry© Nuclear Decommissioning Authority 2011. 108

SSEM/2011/4730 June 2011and photo/video surveying. Constraints on the availability of EA resources and costs hasmeant that this additional work will not be delivered at this time.Figure 7.6. Target area for the grab sampling work showing the position of the sea pipelinesand the location of the Aquadopp current profiler deployed to the north of the diffusers fromJune 2010 to February 20117.3.4 Developing the forward programme for offshore monitoringSection 3.3 describes the work done during 2010/11 and discusses the collapse of theparticle transport and dispersion modelling contract with Westlakes Scientific Consulting(WSC). The main aim of the contract with WSC was the development of an improved modelthat would inform offshore monitoring effort. This model was to be used to develop thespecification for an offshore monitoring contract. The failure of the contract to deliver this hasmeant that SL is now looking to award a monitoring contract without the benefit of a validatedmodel. The specification for this contract will therefore need to be different to that previouslyplanned.Although the contract with WSC did not deliver the full work scope, the progress made priorto the collapse of the contract has provided useful information on which to develop amonitoring specification. Discussions with the DSRL contractor (Land & Marine) have alsoproved very useful in understanding what information the monitoring contractor may need togather before committing to a monitoring programme. SL is now looking to develop a© Nuclear Decommissioning Authority 2011. 109

SSEM/2011/4730 June 2011contract model that is phased towards achieving a programme of physical monitoring; and islooking to the supply chain to propose and develop solutions to detect and recover particlesfrom the seabed.The first phase will build on the information already gathered from beach monitoring and theoffshore information gathering work (Aqaudopp, sediment sampling, swath bathymetry etc) toset performance criteria and then seek demonstration of detection and recovery capability.To achieve this it is anticipated that the successful contractor(s) will need to undertake theirown offshore survey work; modelling; and optioneering; before demonstrating capability todetect and recovery particles (including alpha-rich) underwater (eg by trial deployment).Successful completion of Phase 1 will then allow the contractor(s) to proceed to Phase 2 – aprogramme of offshore monitoring. SL has produced the following Task Specification (Figure7.6) that sets out what needs to be done to achieve Phase 1. The breakdown of necessarytasks is provided in the programme schedule and contract development and award will besupported by SL commercial and contract specialists.© Nuclear Decommissioning Authority 2011. 110

SSEM/2011/4730 June 2011© Nuclear Decommissioning Authority 2011. 111

SSEM/2011/4730 June 2011Figure 7.7. Draft Task Sheet for work to progress offshore monitoring.© Nuclear Decommissioning Authority 2011. 112

SSEM/2011/4730 June 20117.4 Future Beach Monitoring Assessment Work ProgrammeThe beach monitoring assessment work programme is updated regularly and takes accountof new information and results of completed assessments. Fundamental to the workprogramme is a specification of detailed objectives. These objectives and the work plannedto achieve them are discussed with stakeholders and agreed with the Environment Agency.The outline below gives an indication of the scope of the work programme listed under broadtopic areas. The assessment work programme will then be incorporated into the overarching'Particles in the Environment' work programme.Exposure pathways Identify and collect the most appropriate habit data for inclusion in risk assessmentcalculations. Review and collate beach find exposure pathways, together with their associatedprobability of exposure, for the beach monitoring worker and the general public. Assess the seasonal affect on the general public's contact potential for all beach finds andspecific subgroups of finds. Review and collate relevant environmental monitoring measurements and samplingresults and assess how they relate to beach finds and the risk to the public.Beach find characterisation For beach find subgroups, identified by their significant characteristics (e.g. dimensions,radionuclide content etc.), identify all significant radionuclides, and assess their activityranges. Review the internal and external analysis schedules to ensure they maximise the gainsfrom the resources available (i.e. practicable, timely, and useful).Beach monitoring Assess the total find population and its component populations (i.e. sub-sea, total for allbeaches and for individual beach populations) for each subgroup of finds. Assess for subgroups of finds the transfer rate between sub-sea populations and beachpopulations. Assess for subgroups of finds the movement of the populations between beaches andwithin beach areas. Assess for all finds and subgroups of finds the affect of the relative and absolute depth offinds. Assess for all finds and subgroups of finds the extended and local find spatial distribution. For subgroups of finds define 'footprints' for consistent statistical analysis and reporting. Assess for all finds and subgroups of finds the affect of sand grain size on particletransportation. Assess if data currently gathered maximises its use in statistical analysis. Assess if the monitoring technique currently used maximises the data gathered withrespect to monitored area and/or monitoring volume and justify any changes proposed. Gather the data needed by the sub-sea working group to judge the BAT work programmerequired for sub-sea assessment.7.5 Summary of costsDetailed information on costs has not been provided in previous annual reports on beachmonitoring and offshore monitoring work. Inclusion of this section in this year’s report is notintended to provide detailed cost breakdowns of all the work that has been done or isplanned, but is aimed at providing the reader with a clearer understanding of the order ofcosts that are associated with the particles in the environment work scope.© Nuclear Decommissioning Authority 2011. 113

SSEM/2011/4730 June 2011From 2008/09 onwards, the annual cost of external contracts and SL EnvironmentalManagement staff required to deliver the particles work programme has been in excess of£1M. This excludes the costs to SL for internal laboratory services and for costs that arerecovered from SL by the Environment Agency. If charged to this work directly, internallaboratory costs are estimated to be approximately £100 per beach find. With over 1300beach finds to date, internal analysis is estimated to have cost in excess of £130,000 to date.SL does not receive a detailed breakdown of the costs recovered by EA to cover regulationof the site and its operations. These costs include the time spent by individual Inspectors andcover the costs of contracts that EA award (eg the HPA Risk Assessment). It is estimatedthat these charges could add between £150,000 and £250,000 per year.The most significant area of spend to date has been the cost of the contract for beachmonitoring operations. Even with the introduction of a reduced area monitoring programmefor 2011/12, this element still represents close to £0.5M per year. Other significant costscover the external analysis that SL is having carried out under contract. For 2010/11 thecontract awarded for transport and dispersion modelling for offshore particles would havetaken spending for that year over £1.5M. The collapse of that contract resulted in a costreduction, although the total spend was still in excess of £1M.For 2011/12, the budget for the year is again in excess of £1M, reflecting the significantamount of work that continues. As SL moves towards award of an offshore monitoringcontract estimated costs will rise sharply, with current estimates for 2012/13 potentiallyresulting in a doubling of the current costs, to in excess of £2M. Offshore monitoring itselfhas the potential to see these values rise even further. These forecasted increases need tobe considered against the backdrop of enhanced financial constraints that are currently beingapplied across all government spending. Each year Sellafield Ltd evaluates the total costs torun the site and the deliver the various projects required to safely operate a site of this sizeand complexity. Particles in the Environment, is one of many work streams that must beassessed against site priorities; and where funding allocation needs to be cognisant ofproportionality in terms of hazard and risk reduction.© Nuclear Decommissioning Authority 2011. 114

SSEM/2011/4730 June 20118. Programme of WorksThe attached programme (Figure 8.1) captures the main work tasks that are underway thisfinancial year (2011/12) and sets out indicative tasks describing how future work is currentlybeing planned or envisaged out to the end of March 2013. This programme is a developmentfrom that submitted to EA last year, in that it provides significantly more detail.As with all programmes for complex and long-duration projects the number of tasks is largeand the ability to fully describe them in a programme format is limited. The programmetherefore needs to be considered together with the discussion provided in the main body ofthe report.The intent is to maintain the programme as a live document that will be reviewed andupdated as work progresses. SL is also conscious that the programme will need to beagreed with the EA. Some of the tasks and their scheduling have not been discussed withthe EA. The attached version is therefore a snapshot that SL wishes to use as the basis onwhich agreement can be sought with the EA.Figure 8.1. Programme of works(Begins on next page).© Nuclear Decommissioning Authority 2011. 115

ID WBS Task Name Duration Start Finish Predecess 2011 2012 2013Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q41 1 2011/2012 Project Start 0 days Mon 04/04/11 Mon 04/04/1104/042 2 Management of Beach Monitoring Programme (2011/2012) 325 days Mon 04/04/11 Mon 28/05/123 2.1 Beach monitoring operations 280 days Mon 04/04/11 Fri 30/03/12 1SS4 2.2 Vehicle Recovery Demonstration 1 day Fri 06/05/11 Fri 06/05/11 3SS5 2.3 Contractor monitoring report 45 days Fri 30/03/12 Mon 28/05/12 36 2.4 Quarterly Reviews of monitoring data - area covered/find rate 259.05 days Mon 09/05/11 Fri 06/04/12External Contract - Beach MonitoringExternal Contract - Beach MonitoringExternal Contract - Beach Monitoring7 2.4.1 Quarterly Reviews of monitoring data - area covered/find rate 1 5 days Fri 01/07/11 Thu 07/07/11 3SS8 2.4.2 Quarterly Reviews of monitoring data - area covered/find rate 2 5 days Mon 03/10/11 Fri 07/10/11 79 2.4.3 Quarterly Reviews of monitoring data - area covered/find rate 3 5 days Mon 02/01/12 Fri 06/01/12 810 2.4.4 Quarterly Reviews of monitoring data - area covered/find rate 4 5 days Mon 02/04/12 Fri 06/04/12 911 2.4.5 Quarterly Contract Progress Meeting 216.22 days Mon 09/05/11 Mon 13/02/1212 2.4.5.1 Quarterly Contract Progress Meeting 1 0 days Mon 09/05/11 Mon 09/05/11 3SS13 2.4.5.2 Quarterly Contract Progress Meeting 2 0 days Mon 08/08/11 Mon 08/08/11 1214 2.4.5.3 Quarterly Contract Progress Meeting 3 0 days Mon 14/11/11 Mon 14/11/11 1315 2.4.5.4 Quarterly Contract Progress Meeting 4 0 days Mon 13/02/12 Mon 13/02/12 1416 2.5 Monthly Progress Report 259.46 days Mon 09/05/11 Mon 09/04/1217 2.5.1 Monthly Progress Report 1 0 days Mon 09/05/11 Mon 09/05/11 3SS18 2.5.2 Monthly Progress Report 2 0 days Mon 13/06/11 Mon 13/06/11 1719 2.5.3 Monthly Progress Report 3 0 days Mon 11/07/11 Mon 11/07/11 1820 2.5.4 Monthly Progress Report 4 0 days Mon 08/08/11 Mon 08/08/11 1921 2.5.5 Monthly Progress Report 5 0 days Mon 12/09/11 Mon 12/09/11 2022 2.5.6 Monthly Progress Report 6 0 days Mon 10/10/11 Mon 10/10/11 2123 2.5.7 Monthly Progress Report 7 0 days Mon 14/11/11 Mon 14/11/11 2224 2.5.8 Monthly Progress Report 8 0 days Mon 12/12/11 Mon 12/12/11 2325 2.5.9 Monthly Progress Report 9 0 days Mon 09/01/12 Mon 09/01/12 2426 2.5.10 Monthly Progress Report 10 0 days Mon 13/02/12 Mon 13/02/12 2527 2.5.11 Monthly Progress Report 11 0 days Mon 12/03/12 Mon 12/03/12 2628 2.5.12 Monthly Progress Report 12 0 days Mon 09/04/12 Mon 09/04/12 2729 2.6 Detailed analysis of beach finds (Management of Serco / NPL151 days Mon 04/04/11 Fri 14/10/11contract) - 2011/201230 2.6.1 Data Review 140 days Mon 04/04/11 Fri 30/09/11 1SS31 2.6.2 Analysis Hold Points 0 days Mon 04/04/11 Mon 04/04/11 30SS32 2.6.3 Contractor analysis report 11 days Fri 30/09/11 Fri 14/10/11 31,3033 2.6.4 Final review 11 days Fri 30/09/11 Fri 14/10/11 32SS34 2.6.5 Quarterly Contract Progress Meetings 150.27 days Mon 04/04/11 Fri 14/10/1135 2.6.5.1 Quarterly Contract Progress Meetings 1 0 days Mon 04/04/11 Mon 04/04/11 30SS36 2.6.5.2 Quarterly Contract Progress Meetings 2 0 days Fri 29/04/11 Fri 29/04/11 3537 2.6.5.3 Quarterly Contract Progress Meetings 3 0 days Fri 29/07/11 Fri 29/07/11 3638 2.6.5.4 Quarterly Contract Progress Meetings 4 0 days Fri 14/10/11 Fri 14/10/11 3739 2.7 Beach Monitoring 2011/2012 Programme review (pre June 2012submission work)40 2.7.1 Annual Review of objectives to provide prioritised detailedobjectives41 2.7.1.1 Annual Review of objectives to provide prioritised detailedobjectives for 2011/2012 (pre-project start date)42 2.7.1.2 Annual Review of objectives to provide prioritised detailedobjectives for 2012/201343 2.7.2 Develop 2012/2013 assessment work programmes toachieve prioritised detailed objectives44 2.7.2.1 Beach finds & monitoring assessment work programmebased on SL experience to date, Jacobs' GIS tools &Glasgow University Stats/GIS methodology advice.280.59 days Mon 04/04/11 Fri 30/03/12280.59 days Mon 04/04/11 Fri 30/03/120 days Mon 04/04/11 Mon 04/04/11 1SS46 days Wed 01/02/12 Fri 30/03/12 3SS46 days Wed 01/02/12 Fri 30/03/1246 days Wed 01/02/12 Fri 30/03/12 1SSEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management Team09/0508/0814/1113/0209/0513/0611/0708/0812/0910/1014/1112/1209/0113/0212/0309/04External Contract - Beach Monitoring04/04External Contract - Beach MonitoringExternal Contract - Beach Monitoring04/0429/0429/0714/1004/04Environmental Management TeamEnvironmental Management TeamProject: Particles in the EnvironmentDate: Wed 29/06/11TaskSplitProgressMilestoneSummaryProject SummaryExternal TasksExternal MilestoneDeadlinePage 1

ID WBS Task Name Duration Start Finish Predecess 2011 2012 2013Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q445 2.7.2.2 Sub-sea assessment work programme based on available46 days Wed 01/02/12 Fri 30/03/12 1SSEnvironmental Management Teamdata & contractor reports46 3 Beach Monitoring Statistics 209.89 days Mon 04/04/11 Fri 30/12/1147 3.1 Management of external statistical expert contract 2011/2012 80.54 days Mon 04/04/11 Fri 15/07/1148 3.1.1 Review of Statistical techniques 20 days Mon 04/04/11 Thu 28/04/11 1SS49 3.1.2 Review of sampling strategy 20 days Mon 04/04/11 Thu 28/04/11 48SS50 3.1.3 Develop specification for support tasks 20 days Tue 21/06/11 Fri 15/07/11 48,4951 3.2 Evaluation of beach monitoring statistics advice 2011/2012 149.35 days Tue 21/06/11 Fri 30/12/1152 3.2.1 Investigate application of statistical techniques & incorporate into 31 days Tue 21/06/11 Fri 29/07/11 50SSassessment work programmes53 3.2.2 Investigate how statistical techniques can be used to underpin31 days Tue 21/06/11 Fri 29/07/11 52SSthe beach monitoring programme54 3.2.3 Implementation of Statistical Techniques 118 days Mon 01/08/11 Fri 30/12/11 52,53,5055 4 Prepare for EA Programme annual review (June 2011) 210.19 days Mon 04/04/11 Fri 30/12/1156 4.1 Detailed review of Key Stakeholder Project Requirements 31 days Mon 04/04/11 Thu 12/05/1157 4.1.1 Develop high level objectives from EA monitoring guidance 5 days Mon 04/04/11 Fri 08/04/11 1SS58 4.1.2 Identify Sellafield LTD 'Key Questions' that need to be answered 5 days Tue 05/04/11 Tue 12/04/11 5759 4.1.3 Link 'key questions' to objectives 5 days Thu 07/04/11 Thu 14/04/11 5860 4.1.4 Compare EA/FSA/HPA questions to Sellafield Ltd questions 5 days Mon 11/04/11 Mon 18/04/11 5961 4.1.5 Identify what work has already been completed 10 days Mon 18/04/11 Fri 29/04/11 6062 4.1.6 Identify what gaps exist & areas for future work 10 days Fri 29/04/11 Thu 12/05/11 6163 4.2 Review of analysis data - summary statistics 15 days Mon 04/04/11 Thu 21/04/11 1SS64 4.3 Review contractor monitoring report for 2010/2011 45 days Mon 04/04/11 Tue 31/05/11 1SS65 4.4 Review of Internal analysis data 43 days Mon 04/04/11 Fri 27/05/1166 4.4.1 Review proposed 'Inference' analysis methodology 43 days Mon 04/04/11 Fri 27/05/11 1SS67 4.4.2 Review of analysis data - summary statistics 43 days Mon 04/04/11 Fri 27/05/11 1SS68 4.5 Review of External Analysis data 43 days Mon 04/04/11 Fri 27/05/11 1SS69 4.6 HPA Risk Assessment 196.14 days Thu 21/04/11 Fri 30/12/1170 4.6.1 Review HPA Risk Assessment 5 days Thu 21/04/11 Wed 27/04/11 1SS71 4.6.2 Data provision to HPA 141 days Fri 01/07/11 Fri 30/12/11 7072 4.6.3 Implications of recent synergy data 141 days Fri 01/07/11 Fri 30/12/11 71SS73 4.6.4 Sellafield Ltd particle density estimate 21 days Mon 04/07/11 Fri 29/07/11 71SS74 4.7 Review of external statistical work 19 days Wed 01/06/11 Fri 24/06/11 1SS75 4.8 Review of Aquadopp data 47 days Mon 02/05/11 Thu 30/06/11 1SS76 4.9 Review aerial gamma survey report 69 days Mon 04/04/11 Thu 30/06/11 1SS77 4.10 Review rationale for 2011/2012 monitoring programme 69 days Mon 04/04/11 Thu 30/06/11 1SS78 4.11 Annual review of objectives to provide prioritised detailed69 days Mon 04/04/11 Thu 30/06/11 1SSobjectives for 2011/201279 4.12 Make annual Submission to EA 0 days Thu 30/06/11 Thu 30/06/11 57,58,59,680 5 EA Programme Update Meeting (July 2011) 5 days Mon 11/07/11 Fri 15/07/1181 5.1 Prepare for EA Programme update meeting 5 days Mon 11/07/11 Fri 15/07/11 7982 5.2 Attend EA Programme update meeting 0 days Fri 15/07/11 Fri 15/07/11 8183 6 Investigate Subsea monitoring operations options for 2011/2012 29.86 days Mon 18/04/11 Wed 25/05/1184 6.1 Investigate options for trial of Dounreay ROV 15 days Mon 18/04/11 Thu 05/05/11 6285 6.2 Confirm Contractual position / constraints. 5 days Thu 05/05/11 Wed 11/05/11 8486 6.3 Meet with Dounreay & Contractor to consider operational0 days Tue 17/05/11 Tue 17/05/11 85options/constraints87 6.4 Internal review of potential for conducting trial 5 days Thu 19/05/11 Wed 25/05/11 8688 7 End of Concept phase gate review 5 days Fri 15/07/11 Fri 22/07/11 82,84,85,889 8 Grab Sampling Programme 2011/2012 161.22 days Thu 19/05/11 Wed 14/12/11External Contract - Beach MonitoringExternal Contract - Beach MonitoringEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management Team30/06Environmental Management Team15/07Environmental Management TeamEnvironmental Management Team17/05Environmental Management TeamProject Steering GroupProject: Particles in the EnvironmentDate: Wed 29/06/11TaskSplitProgressMilestoneSummaryProject SummaryExternal TasksExternal MilestoneDeadlinePage 2

ID WBS Task Name Duration Start Finish Predecess 2011 2012 2013Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q490 8.1 Develop EA sediment Grab Sampling Specification 58.22 days Thu 19/05/11 Tue 02/08/1191 8.1.1 Liaise with EA/Nuvia regarding specification - How, What, Where 56 days Thu 19/05/11 Fri 29/07/11 1SS& When?92 8.1.2 Agree Cost & Recovery route for EA work 56 days Thu 19/05/11 Fri 29/07/11 91SS93 8.1.3 Liaise with Babcock Laboratory on sample analysis requirements- number of samples, analytes, detection limits.42 days Thu 09/06/11 Tue 02/08/11 92SSEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management Team94 8.1.4 Agree analysis costs & contractual arrangements 24 days Fri 01/07/11 Tue 02/08/11 93SS95 8.2 EA grab sampling operations 2011/2012 103 days Tue 02/08/11 Wed 14/12/1196 8.2.1 Sampling Operations 22 days Tue 02/08/11 Wed 31/08/11 91,92,93,997 8.2.2 Sediment sample delivery to labs 1 day Wed 31/08/11 Thu 01/09/11 9698 8.2.3 Sample analysis 40 days Thu 01/09/11 Mon 24/10/11 9799 8.2.4 Review grab sampling data & generate a report 40 days Mon 24/10/11 Wed 14/12/11 98100 8.2.5 Present report to the EA 0 days Wed 14/12/11 Wed 14/12/11 99101 9 Develop a Particle transport & model specification 47 days Fri 01/07/11 Wed 31/08/11102 9.1 Collate data on Sealine Condition 47 days Fri 01/07/11 Wed 31/08/11 1103 9.2 Collate sub-sea monitoring data 47 days Fri 01/07/11 Wed 31/08/11 102SS104 9.3 Collate information on non-natural particle movement/distribution 47 days Fri 01/07/11 Wed 31/08/11 103SS105 9.4 Collate data on PSPWG 47 days Fri 01/07/11 Wed 31/08/11 104SS106 10 Project Definition Phase Documents 50 days Wed 31/08/11 Thu 03/11/11107 10.1 Define the Project scope 5 days Wed 31/08/11 Tue 06/09/11 88108 10.2 Define the project Risk Management Plan 10 days Tue 06/09/11 Mon 19/09/11 107109 10.3 Define the project Stakeholder Management plan 5 days Mon 19/09/11 Mon 26/09/11 108110 10.4 Define the project Communications Management plan 5 days Mon 26/09/11 Mon 03/10/11 109111 10.5 Define the project Business Case 10 days Mon 03/10/11 Fri 14/10/11 108,109,11112 10.6 Define a project Quality Management Plan 5 days Fri 14/10/11 Fri 21/10/11 111113 10.7 Define the Project Management Plan 10 days Fri 21/10/11 Thu 03/11/11 112114 11 Develop a Sub-sea Investigation Project for 2012 onwards 490.81 days Mon 04/07/11 Fri 29/03/13115 11.1 Agree OJEU strategy 22 days Mon 04/07/11 Mon 01/08/11 1SS116 11.2 Prepare detailed scope for OJEU publication in 2011/2012 182.32 days Mon 01/08/11 Fri 23/03/12117 11.2.1 Prioritise / bound scope of work for year 1 & update business30 days Mon 01/08/11 Thu 08/09/11 115case118 11.2.2 Collate currently available data 30 days Wed 31/08/11 Mon 10/10/11 103,104,10119 11.2.3 Generate Request for Tender 30 days Mon 10/10/11 Wed 16/11/11 118120 11.2.4 End of Definition phase gate review 5 days Wed 16/11/11 Wed 23/11/11 119,113121 11.2.5 Publish request for tender on OJEU 0 days Wed 23/11/11 Wed 23/11/11 120122 11.2.6 OJEU Tender period 60 days Wed 23/11/11 Thu 09/02/12 121123 11.2.7 Review/score tender bids 2 days Thu 09/02/12 Fri 10/02/12 122124 11.2.8 'Cooling-Off Period 15 days Fri 10/02/12 Thu 01/03/12 123125 11.2.9 Project gate review 0 days Thu 01/03/12 Thu 01/03/12 124126 11.2.10 Award Contract for 2012/2013 0 days Thu 01/03/12 Thu 01/03/12 125127 11.2.11 Contract acceptance deadline 0 days Fri 23/03/12 Fri 23/03/12 126128 11.3 Deliver Contract in 2012/2013 to define a Sub-sea MonitoringBPM/BPEO Detailed Scope / outline task specification240 days Mon 02/04/12 Wed 06/02/13Environmental Management TeamExternal Contract - sub-sea monitoringExternal Contract - sub-sea monitoringBabcock NuclearEnvironmental Management Team14/12Environmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamProject SupportProject SupportProject SupportProject SupportProject SupportProject SupportEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamProject Steering Group23/11Source Evaluation Board01/0301/0323/03129 11.3.1 External Contract Start 0 days Mon 02/04/12 Mon 02/04/12 127130 11.3.2 Detection Capabilities 120 days Mon 02/04/12 Tue 04/09/12131 11.3.2.1 Evaluation of Sub-sea alpha detection capabilities 120 days Mon 02/04/12 Tue 04/09/12 129SS132 11.3.2.2 Evaluation of sub-sea beta detection capabilities 120 days Mon 02/04/12 Tue 04/09/12 129SS133 11.3.2.3 Evaluation of sub-sea gamma detection capabilities 120 days Mon 02/04/12 Tue 04/09/12 129SS134 11.3.3 Sub-sea particle detection & recovery modelling 120 days Tue 04/09/12 Wed 06/02/13135 11.3.3.1 Develop recovery options 120 days Tue 04/09/12 Wed 06/02/13 131,132,1302/04External Contract - sub-sea monitoringExternal Contract - sub-sea monitoringExternal Contract - sub-sea monitoringExternal Contract - sub-sea monitorinProject: Particles in the EnvironmentDate: Wed 29/06/11TaskSplitProgressMilestoneSummaryProject SummaryExternal TasksExternal MilestoneDeadlinePage 3

ID WBS Task Name Duration Start Finish Predecess 2011 2012 2013Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4136 11.3.3.2 Conceptual model development 120 days Tue 04/09/12 Wed 06/02/13 131,132,13External Contract - sub-sea monitorin137 11.3.3.3 Development of BAT/BPEO case 120 days Tue 04/09/12 Wed 06/02/13 131,132,13138 11.3.3.4 Complete detailed swathe bathymetry of Sellafield off-shore 120 days Tue 04/09/12 Wed 06/02/13 131,132,13area139 11.3.4 Develop initial sub-sea monitoring strategy 60 days Tue 04/09/12 Tue 20/11/12 131,132,13140 11.3.5 Model the Dounreay ROV for the Sellafield Environment 120 days Tue 04/09/12 Wed 06/02/13 131,132,13141 11.3.6 Develop the specification for a Dounreay ROV trial at Sellafield 120 days Tue 04/09/12 Wed 06/02/13 131,132,13External Contract - sub-sea monitorinExternal Contract - sub-sea monitorinExternal Contract - sub-sea monitoringExternal Contract - sub-sea monitorinExternal Contract - sub-sea monitorin142 11.3.7 Develop system deployment 120 days Tue 04/09/12 Wed 06/02/13 131,132,13143 11.3.8 External Contract Project End 0 days Wed 06/02/13 Wed 06/02/13 138,135,13144 11.3.9 Project gate review 0 days Wed 06/02/13 Wed 06/02/13 143145 11.4 Develop a Contact for delivery of a sub-sea monitoring40 days Wed 06/02/13 Fri 29/03/13programme in 2013/2014146 11.4.1 Prioritise / bound scope of work & update business case 20 days Wed 06/02/13 Mon 04/03/13 144147 11.4.2 Collate currently available data 20 days Wed 06/02/13 Mon 04/03/13 146SS148 11.4.3 Process a Purchase Order for Services 15 days Mon 04/03/13 Fri 22/03/13 147,146149 11.4.4 Award Contract for 2013/2014 5 days Fri 22/03/13 Fri 29/03/13 148150 12 Routine Programme Lifetime Plan 12 planning 159.46 days Thu 01/09/11 Mon 26/03/12External Contract - sub-sea monitorin06/0206/02Environmental Management TeamEnvironmental Management TeamEnvironmental Management TeaEnvironmental Management Te151 12.1 Determine the scope for the Beach Monitoring contract for 2012/2013 30 days Thu 01/09/11 Mon 10/10/11 1SS& obtain cost estimates152 12.2 Determine the scope for the Statistical Expert (Beach Monitoring)30 days Thu 01/09/11 Mon 10/10/11 1SScontract for 2012/2013 obtain cost estimates153 12.3 Determine the scope for the GIS support contract obtain cost30 days Thu 01/09/11 Mon 10/10/11 1SSestimates154 12.4 Determine the scope for the detailed beach finds analysis contract for 30 days Thu 01/09/11 Mon 10/10/11 1SS2012/2013 obtain cost estimates155 12.5 Submit cost estimates and business case for inclusion in BoE for15 days Mon 10/10/11 Fri 28/10/11 151,152,152012/13156 12.6 Gain confirmation of 2012/2013 funding availability in LTP 12 0 days Fri 28/10/11 Fri 28/10/11 155157 12.7 Commercial Contract POs 20 days Wed 29/02/12 Mon 26/03/12Environmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management TeamProject Support28/10158 12.7.1 Beach Monitoring Contract PO for 2012/2013 20 days Wed 29/02/12 Mon 26/03/12 151,156159 12.7.2 Stats expert contract PO for 2012/2013 20 days Wed 29/02/12 Mon 26/03/12 152,156160 12.7.3 GIS support contract PO for 2012/2013 20 days Wed 29/02/12 Mon 26/03/12 153,156161 12.7.4 Beach Finds detailed analysis contract PO for 2012/2013 20 days Wed 29/02/12 Mon 26/03/12 154,156162 13 Identification of particle sources & pathways 14 days Mon 14/11/11 Wed 30/11/11Environmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management Team163 13.1 Identification of particle sources & pathways: Beta Rich particle14 days Mon 14/11/11 Wed 30/11/11 33analysis / evaluation164 13.2 Review of on-site particle exclusion work 14 days Mon 14/11/11 Wed 30/11/11 163SS165 13.3 PSPWG work 14 days Mon 14/11/11 Wed 30/11/11 164SS166 13.4 Evaluation of historic activities & their environmental impact. 14 days Mon 14/11/11 Wed 30/11/11 165SS167 14 Periodic Stakeholder Metings 248.65 days Mon 04/04/11 Mon 20/02/12Environmental Management TeamEnvironmental Management TeamEnvironmental Management TeamEnvironmental Management Team168 14.1 WCSSG Env. Sub Committee Meetings 140.54 days Thu 26/05/11 Thu 24/11/11169 14.1.1 Update WCSSG Env. Sub committee (May 2011) 0 days Thu 26/05/11 Thu 26/05/11 1SS170 14.1.2 Update WCSSG Env. Sub committee (Nov 2011) 0 days Thu 24/11/11 Thu 24/11/11 1SS171 14.2 EA Programme Update Meeting October 2011 9.73 days Mon 17/10/11 Fri 28/10/1126/0524/11172 14.2.1 Prepare for EA programme update meeting 5 days Mon 17/10/11 Fri 21/10/11 82173 14.2.2 Attend EA Programme update meeting 0 days Fri 28/10/11 Fri 28/10/11 172174 14.3 HPA Technical review Meeting Nov 2011 0 days Tue 01/11/11 Tue 01/11/11 1SS175 14.4 Seabed working group meetings 113.51 days Thu 07/07/11 Thu 01/12/11Environmental Management Team28/1001/11176 14.4.1 Seabed working group meeting (July 2011) 0 days Thu 07/07/11 Thu 07/07/11 1SS177 14.4.2 Seabed working group meeting (September 2011) 0 days Thu 01/09/11 Thu 01/09/11 176178 14.4.3 Seabed working group meeting Dec 2011 0 days Thu 01/12/11 Thu 01/12/11 177179 14.5 EA Programme update meeting Feb 2012 23.78 days Mon 02/01/12 Wed 01/02/1207/0701/0901/12180 14.5.1 Prepare for EA Programme update meeting 5 days Mon 02/01/12 Fri 06/01/12 173181 14.5.2 Attend EA Programme update meeting 0 days Wed 01/02/12 Wed 01/02/12 180Environmental Management Team01/02Project: Particles in the EnvironmentDate: Wed 29/06/11TaskSplitProgressMilestoneSummaryProject SummaryExternal TasksExternal MilestoneDeadlinePage 4

ID WBS Task Name Duration Start Finish Predecess 2011 2012 2013Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4182 14.6 COMARE (SWG) meeting Feb 2012 0 days Mon 20/02/12 Mon 20/02/12 1SS20/02183 14.7 Multi-Agency Meetings (TBC) 0 days Mon 04/04/11 Mon 04/04/11 1SS184 15 Project Ends 0 days Fri 29/03/13 Fri 29/03/13 28,38,10,104/0429/03Project: Particles in the EnvironmentDate: Wed 29/06/11TaskSplitProgressMilestoneSummaryProject SummaryExternal TasksExternal MilestoneDeadlinePage 5

SSEM/2011/4730 June 2011ReferencesBeddow H. 2010a. Large scale beach trials to evaluate the operational performance ofGroundhog Evolution2. Nuvia.Beddow H. 2010b. Large scale beach trials to evaluate the operational performance ofGroundhog Synergy system. Nuvia.Brown J, Etherington G. 2011. Health risks for radioactive objects on beaches in the vicinityof the Sellafield site. HPA-CRCE-018.Clough MEJ. 2010. Offshore Monitoring at Sellafield: Status and Progress Report- Workdone to March 2010. SSEM/2010/33 (March 2010).Clough MEJ. 2009. Offshore Monitoring at Sellafield: Status and Progress Report- Workdone to March 2010. SSEM/2009/27 (March 2009).Beach Monitoring BPM Desk Study of techniques for detecting radioactive particles onbeaches Study October 2008- Serco (SERCO/TAS/2301/002)Brown J and Etherington G. 2011. Health Risks from Radioactive Objects on Beaches in thevicinity of the Sellafield Site. HPA-CRCE-018.Clacher A, Cowper M, Stone N, Holton D,. Analysis of Beach monitoring Finds - SecondTranche, TCS/003890/003 Issue 1, 21 July 2010.Cooper J. 2011. Letter to S Page re: Sellafield Radioactive Particles in the Environment on21 April 2011.Dalton A. 2010 Beach Monitoring BPM Review. (SSEM/2010/75) October 2010.Dalton A. Progress update on beach monitoring R&D Action Plan. SSEM/2010/25 (March2010)Davies M. 2008. Groundhog Evolution 2 Limits of Detection for 241 Am, 90 Sr, 60 Co and 137 Cs.87204/TR/013 issue A, April 2008.D'Souza J. 2010. Annual Beach Monitoring Report 2009/10. SSEM/2010/59, Issue 1, 30 July2010.D’Souza J, Annual Beach Monitoring Report 2008/09. SSEM/2009/75, Issue 1, July 2009.Sellafield Ltd.Desmond J. 2009. Sellafield Beach Monitoring Best Practicable Means Study.SSEM/2008/121 (March 2009).Etherington G. 2011. Letter to TG Parker on 12 May 2011 re: Dosimetry Assessment forNuvia workers engaged in beach monitoring.Etherington G, Gregoratto D, Brichall A. 2011. Dosimetry assessment for Nuvia workersengaged in beach monitoring. Health Protection Agency. CRCE-TOX-05-2011.Groves C, Little P. 2010. Review of particle age estimation methodology and agedetermination of Sellafield beach particles. Issue 2. NNL (09)10702. RESTRICTED.© Nuclear Decommissioning Authority 2011. 121

SSEM/2011/4730 June 2011Hackney PD, Dalton AP, Courtney B. 2010. Report on the potential sources & pathways forthe alpha-rich particulate finds being detected and recovered from beaches associated withthe Sellafield nuclear licensed site in west Cumbria. SSEM/2009/23 issue 1 (RESTRICTED),16 June 2010.Hall D. 2011. Results of Beach Monitoring around Sellafield April 2010 – March 2011.87257/TR/008 Issue 1.Hemming K, Summary report – detection and recovery of radioactive particulate frombeaches associated with the Sellafield nuclear licensed site. SSEM/2008/64, Issue 2.Sellafield Ltd.HPA-CRCE-018 April 2011, Health Risks from Radioactive Objects on Beaches in theVicinity of the Sellafield Site, Brown J, Etherington G, and HPA-CRCE-018 (supplement)April 2011, Supporting Information for the Assessment of the Health Risks from RadioactiveObjects on Beaches in the Vicinity of the Sellafield Site, Oatway W, Brown J, Etherington G,Anderson T, Fell T, Eslava-Gomez A, Hodgson A, Pellow PGD and Youngman MICRP Publication 3 March 2007, The 2007 Recommendations of the InternationalCommission on Radiological Protection.Locke J. 2010. Review of potential Beach Monitoring techniques.(SERCO/TAS/4772/001)September 2010.Oatway W, Brown J, Etherington G, Anderson T, Fell T, Eslava-Gomez A, Hodgson A,Pellow PGD, Youngman M. 2011. Supporting information for the assessment of the healthrisks from radioactive objects on beaches in the vicinity of the Sellafield site. HPA-CRCE-018(supplement), ISBN 978-0-85951-693-8, April 2011.Pellow PGD, Hodgson A, Etherington G, Ham G, Fell TP, Harrison JD. 2010. The intestinalabsorption of plutonium and americium from a further five particles recovered from Cumbrianbeaches. HPA: CRCE-DA-13-2010-Revision_1, June 2010.Randles T. 2010. Potential Exposure Pathways for Sellafield Beach Monitoring Workers.Nuvia Internal Technical Report. December 2010 (87257/TR/006).Scott EM, Tyler AN. 2011. Radioactive particle monitoring: statistical techniques, (Report I),21 June 2011.Scott EM, Tyler AN. 2011. Radioactive particle monitoring: statistical sampling techniques,(Report II), 22 June 2011.Tossell P. Letter to S Page, Environment Agency, 15/03/2011. Health Protection Agency.Cowper M, Stone N, Holton D,. Analysis of Beach monitoring finds - Final Report Issue 2,SERCO/002037/1, December 2009.Vives Lynch S. 2006. Probability distribution for the beaching of particles based on acontinuous annual discharge from the British Nuclear Group, Sellafield site. WestlakesScientific Consulting (050160/02).Westlakes Scientific Consulting. 2006. Probability distribution for the beaching of particlesbased on continuous annual discharge from the British Nuclear Group, Sellafield Site.050160/02, First issue.© Nuclear Decommissioning Authority 2011. 122

© Nuclear Decommissioning Authority 2011

SSEM/2011/4730 June 2011Appendix 12010/11 Beach Monitoring Coverage Maps

Allonby monitoring extent for 2010/11.

Harrington monitoring extent and associated beach finds for 2010/11.

Parton monitoring extent for 2010/11.

Whitehaven North/Harbour monitoring extent and associated beach finds for 2010/11.

St Bees monitoring extent and associated beach finds for 2010/11.

Nethertown monitoring extent for 2010/11.

Seascale monitoring extent and associated beach finds for 2010/11.

Drigg monitoring extent and associated beach finds for 2010/11.

SSEM/2011/4730 June 2011Appendix 2Interpretation of Swath Bathymetry in the EasternIrish Sea for Sellafield Ltd© Nuclear Decommissioning Authority 2011.

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Sellafield Particle Work Programme2010ESR87 Phase 1Interpretation of Swath Bathymetry in the eastern Irish SeaforSellafield LtdDecember 2010prepared by:Kershaw, P.J., Barrie, J., Dolphin, T. & Rees, J.M.The Centre for Environment, Fisheries & Aquaculture Science (Cefas)Pakefield Road, Lowestoft, Suffolk, NR33 0HTcontact: jon.rees@cefas.co.ukor peter.kershaw@cefas.co.ukCommercial-in-confidence

Contents1. Introduction ....................................................................................................................... 31.1 Background to report ................................................................................................... 31.2 Objectives ................................................................................................................... 32. Methods ............................................................................................................................ 33. Results .............................................................................................................................. 43.1 Analysis of existing swath bathymetry ......................................................................... 43.2 Options for acquiring new bathymetric data ............................................................ 83.3 Interpretation of gross geomorphological features (objective 2) ................................. 103.4 Additional sources of existing bathymetry data (objective 3) ...................................... 113.5 Recommendations for the design of the offshore monitoring programme (objective 4)........................................................................................................................................ 134 Conclusions ..................................................................................................................... 13

1. Introduction1.1 Background to reportThis report concerns one module of Phase 1 of a project (ESR87) being conducted by Cefason behalf of Sellafield Ltd. (SL), concerning the interpretation of swath bathymetry recordsheld by SL. It forms part of a larger investigation of the sources, sinks and transportpathways of radioactive ‘particles’ found along the foreshore near Sellafield, Cumbria.Originally Cefas was sub-contracted to Westlakes Scientific Consulting Ltd. (WSCL), onbehalf of Sellafield, and an interim report was submitted to WLSC in April 2010, before thecompany went into Administration. This report represents a summary of the findings and isthe key deliverable.1.2 ObjectivesThe objectives of this project were to:1. Analyse and interpret the 2009 survey swath bathymetry data held by SL;2. Compare the 2009 survey data with similar data from 2002 to establishchanges in bathymetry and bedform characteristics;3. Acquire and analyse adjacent nearshore single beam bathymetry data fromSeazone Solutions Ltd., to extend the available bathymetry shoreward; and4. Report findings with particular reference to informing the sampling design ofthe offshore monitoring programme, the sampling design of a deliberatetracer release, and informing model parameterisation.Objective 1 had a completion date for March 2010 with subsequent objectives to bedelivered in the FY10/11.2. MethodsSwath or multibeam bathymetry provides a detailed picture of the depth and seabedmorphology. Images can be interpreted to provide information about the spatial scale andextent of different bedforms (e.g. scour pits, ripples; Figure 1). This in turn can be used: forplanning sampling/measuring strategies (e.g. to identify the presence of ‘difficult’ ground forsampling); to estimate potential burial depths; to collate with other oceanographicmeasurements, such as current meters; to delineate habitats, and assist in the identificationof species for risk assessment; and, for informing the parameterisation of hydrodynamicmodels. Where time-series data are available these can be used to assess changes in thebathymetry and bedform characteristics. Single beam bathymetry can provide informationabout bed height where swath data are lacking.

Figure 1 - Swath bathymetry of Scroby Sands windfarm, off the east coast of England, shows mobilebedforms (mega-ripples, scour pits, sand wave). The vertical red bars indicate the position ofmonopiles, and the purple line the line of the connecting cable. Red-orange areas indicate shallowerwater.The swath or multibeam survey data held by SL were analysed within the IVS3DFledermaus suite of visualisation and analysis software. This allows analysis of thebathymetry data to be undertaken at horizontal and vertical resolutions appropriate to thescale of the field of vision using a high speed “data mining engine”.3. Results3.1 Analysis of existing swath bathymetryThe “XYZ” data file held by SL was uploaded into the Fledermaus Package using a 1m by1m resolution in order to observe, characterise and map bedforms within the survey area.Figure 2 shows the coverage of the survey along the Cumbrian coastline, and reveals largescalebathymetric features.The swath bathymetry has been used by Halcrow to produce maps of the bathymetry alongthe Sellafield coastline (Figure 3). The data quality is sufficient to delineate large scaleseabed features, e.g. sand banks at a typical horizontal scale of ~100m, or for numericalmodelling purposes which uses a coarse resolution grid (~ 1km). The Halcrow report makesno attempt to go beyond this high-level interpretation.

Figure 2 - Swath bathymetry map superimposed on the Admiralty Chart of the Cumbrian coastline.Reproduced from Admiralty Chart 1826 by permission of the Controller of Her Majesty's StationeryOffice and the UK Hydrographic Office (www.ukho.gov.uk) Arcs Chart Licence F46558002C2B4F56.Not to be used for navigation. Depth scale: 3-5 m red, 5-9 m yellow, 9-14 m green, 14-16 m pale blue,16-19 m mid-blue, 19-20 m dark blue.Figure 3 – Extract from Halcrow report demonstrating large-scale seabed features (Halcrow, 2009)

Figures 4 to 6 show the same data within the Fledermaus package and show the extent ofthe bathymetry survey, the Sellafield pipeline and the two Navigation Markers buoys (redcubes). Note a vertical exaggeration of only 6 times has been applied to the data. This 3Drepresentation of bathymetry data can be viewed in the free iView4D viewer available fromwww.IVS3d.com.Investigation of the bathymetry at a scale of 0 to 10m, which is required to observe,characterise and map seabed bedforms, showed that a number of artefacts were visible inthe data (Figures 4 – 6). These of themselves would not prevent larger-scale features beinganalysed but were of similar amplitude to the smaller-scale features indicative of sedimenttransport. The likely causes of these artefacts include:1) Incomplete coverage2) Incorrect speed of sound correction applied3) Loss of bottom track4) Either poor weather conditions (large waves) and/or an incorrect calibration of theMotion Reference Unit (MRU) creating an artefact of typically 30 cm in the elevationof the seabed.5) Excessive lateral or vertical movement of the vessel, enhanced if the vessel deviatesfrom a regular sampling gridThe possibility of reprocessing the swath bathymetry to remove these artefacts wasinvestigated, but the original raw datasets produced by the Environment Agency were nolonger in existence and thus reprocessing was not possible.In summary, due to the presence of artefacts larger than the bedforms this project set out tostudy, the available swath bathymetry did not allow us to meet the original aims of objective1. The quality is insufficient to observe, delineate or characterise sediment transportfeatures, such as sand waves and ripples, on horizontal scales of 1-10m. No further workwas undertaken using the swath bathymetry data.This conclusion was relayed to WSCL and SL when discovered. Further communication withthe EA Geomatics Unit revealed that they were using ‘a winter survey vessel in far from idealconditions with the MRU working to its limit’. Best practice was applied to the dataprocessing following the advice from a manufacturer's consultant (SEA). The data aretherefore believed to be as good as it was possible to achieve and no further processing ispossible to improve the data quality. The EA also point out that the data only have a 2mhorizontal and +/- 25cm vertical accuracy. The EA therefore suggested ‘it was alwaysunlikely that [we] were going to be able to pick out more subtle seabed features’.

Figure 4 - Swath bathymetry along in the Cumbrian coastline within the Fledermaus 3D visualisationsoftware. The position of the pipe (black line) and the navigation buoys (red cubes) are shown.12Figure 5 - Close-up of Figure 2 at a position near the end of the pipeline. Several artefacts are visible:the raw data density inconsistent and insufficient at outer range of the swath coverage (1) and loss ofbottom track (2). Note: Vertical exaggeration of 6.34Figure 6 - As Close-up of Figure 2 and showing two further artefacts: Incorrect speed of soundcreating U-shaped seabed profiles (3) and either poor weather conditions or MRU calibration errors(4). Note: Vertical exaggeration of 6.

3.2 Options for acquiring new bathymetric dataAs the quality of the available swath bathymetry data was insufficient to identify, map orcharacterise bed forms, a number of alternative solutions to acquire suitable data wereinvestigated. Accurate, high quality maps of bedforms are an essential tool in investigatingsediment transport patterns, pathways and potential sources and sinks of sediment.Potential solutions include:Extend 2010 Environment Agency survey - A new swath survey was planned tobe undertaken along the Cumbrian coastline (Barrow to Workington) in June, Julyand August 2010, carried out by the EA Geomatics Group on behalf of Halcrow. Thework was to be funded by the Agency and a Local Authority. We had been suppliedwith GIS files indicating the proposed locations of the survey lines, extending 3kmfrom shore (Figure 7). We recommended that SL should consider funding the EA toextend the survey:- Up to 5km offshore at selected locations;- Adding survey lines along the Sellafield foreshore; and- Adding a limited number of lines parallel to the coast.The EA had informed us that the survey would be undertaken with equipment able toobtain high resolution swath bathymetry data (Reson 8125 multibeam and POS MVmotion unit). We also recommended that a discussion should take place with the EAon the proposed vertical resolution and quality standards of the data beforecommitting to extending the survey. This would have ensured the data would besuitable to meet the aims of this project. This information was communicated to SLbut we were informed that funding was not available to support the proposedextension.Figure 7 – Planned EA swath bathymetry survey, June-August 2010 (3km offshore from green dotlocations)

Commercial operator – a number of commercial operators exist that have thecapability to undertake a bespoke swath bathymetry survey of the area. Prices willvary depending on the scope of the project and the risks involved. For instance, thestanding charges (mobilisation/demobilisation) start to become less significant for asurvey that will take several weeks to complete. The main risk is the down time dueto poor weather conditions.Invest in Eagle – The Sellafield-owned and operated vessel “Eagle” is capable ofhaving a swath bathymetry system installed. An initial assessment shows that,amongst others, a WASSP swath system (~£40-£50k) (www.wassp.com) orGeoSwath Plus system (~£150k) (www.km.kongsberg.com/geoacoustics) would besuitable for undertaking these surveys. The crew would need to be trained in theoperation of the instruments and processing of the data, with Cefas providing qualitycontrol support. A major benefit of this approach is that the Eagle and crew arealready funded and the vessel can be mobilised quickly if a weather window isforecast, and the vessel is not required for other operations.In summary, three options are proposed in order to acquire the bathymetry information.Table 1 shows these options with potential advantages/disadvantages and costs. Whilstthese are initial estimates they can help inform the decision making process.Table 1 – Potential options for completion of Swath Survey.Option Proposal Rough Cost Advantages Disadvantages1 ExtendEnvironmentAgency surveyTBCVesselalreadyequippedNeed to ensure highquality of the survey toenable bed formcharacterisation.[The 2010 survey hasbeen completed]2 Commercialsurvey£30k-£50k 13 Update Eagle WASSP(~£50k)GeoSwathPlus*(~£150k)High levels ofQualitycontrol. Fast.Uses existingship.*IndustrystandardequipmentMay cost more thanaugmenting EA survey.Need to train personnel.Initial cost.1 Exact Figure to advised

3.3 Interpretation of gross geomorphological features (objective 2)Although bedform features cannot be identified from the 2009 swath bathymetry data, agross interpretation of the morphological changes can be attempted. After gridding the 2002and 2009 surveys in the Fledermaus package on a similar basis, the volumetric differencebetween the surfaces was calculated. This was then exported for visualisation in a GISpackage as shown in Figure 8. This revealed apparent differences in elevation, but there aresignificant uncertainties associated with interpretation due to differences in relative coverageof swath (‘complete’) vs. single beam (

further work has been undertaken to study bathymetric changes from Lidar and swathbathymetry surveys.Figure 9 - Comparison of the bathymetry changes between 2002 and 2009, and the terrestrialelevation changes from Lidar (2006 to 2009) for the area in the vicinity of the Sellafield pipe. Theblack line shows the Mean High Water line; red areas along the single-beam corridors representdeposition, blue areas erosion, and green areas no change (see text for qualifications oninterpretation).3.4 Additional sources of existing bathymetry data (objective 3)Other sources of bathymetric data exist in the Irish Sea. The key resource are those held bythe UKHO, made available through the commercial company SeaZone Solutions Ltd.Exploration of their archive shows the Cumbria coastline to be very sparsely charted within 6kilometres from the shoreline, with the majority charted by lead line between 1837 and 1895and only a small section directly offshore of Sellafield surveyed between 1937 and 1958. Asthese datasets are over 50 years old, and would be unlikely to reveal small scale changes intopography, no further effort has been made to extract them.A number of ad hoc bathymetry surveys have been undertaken in recent years in the NorthEast Irish Sea. The most useful data identified was collected as part of the StrategicEnvironmental Assessment (SEA, 2005). Figure 10 shows the swath bathymetry results fromfive small surveys. Panels 1 and 3 are most pertinent to this project but show conflictingsediment transport patterns. Panel 3, offshore from Sellafield, shows virtually no sedimenttransport with a spherical scour pattern around a wreck. However, Panel 1, near St Bees

Head, shows a marked northerly sediment transport direction with the scour pit from a wreckheading in a north to north north-easterly direction. It should be remembered that theseswath bathymetry maps only give an indication of the processes, magnitude and directionsof when sediment transport last took place. Thus, this could have been on the last tide(within 12hours), on the last Spring tide (last 28 days) or the last winter storm. Similarly,sediment transport occurs in a number of transport regimes under differing wave and currentconditions and the swath bathymetry maps may have only recorded the last of theseregimes.Figure 10 - Figure 17 from DTI (now DECC) SEA report (SEA (2005).Cefas’ research vessel automatically records swath bathymetry data at all times. The trackof the vessel is shown in Figure 11. Inspection of the map shows that the vessel did nottransit the exact area of interest off Sellafield. Only data from near St Bees Head isavailable.

Figure 11 - Extract from OLEX bathymetry processing software showing the swath bathymetry track ofthe RV Cefas Endeavour in the north-eastern Irish Sea in 2009. The track is colour coded asbackscatter or hardness with the purples showing the Sellafield Mud patch and the reds as sand.3.5 Recommendations for the design of the offshore monitoring programme(objective 4)The swath bathymetry will be of use in improving the implementation of hydrodynamicmodels required to predict sediment transport. The data have revealed a number of largescalefeatures that may warrant further investigation as areas of potential deposition orerosion, and areas of rough substrate that may hinder sampling efforts, or act as temporarysinks for mobile particles. Unfortunately the data were insufficient to provide information onsmaller-scale mobile features that would have been very useful for estimating the rates anddirection of particle movement. In turn, this would have provided helpful guidance on thedesign and implementation of a deliberate particle release experiment. We will have to relyon the Aquadopp current meter records (11 th June 2010 – late January 2011) from near theend of the pipe to guide the experimental design, if SL decides to pursue this option. Weshould also like to remind SL that we are in a position to conduct the Woodhead Driftertracer experiment at short notice (i.e. the drifters are tagged and assembled).4 Conclusions1. The existing SL swath bathymetry provides a relatively detailed map of the grossfeatures of the bottom topography.2. It was not possible to distinguish bedforms associated with mobile sediment from theavailable SL swath bathymetry data, due to the relatively poor resolution and a range

of artefacts affecting the original dataset, at a similar scale to the features we weretrying to identify.3. Without information on mobile bedforms it was not possible to deduce sedimenttransport directions and pathways from these data, or of the depth of the seabedinfluenced by these bedforms (to deduce potential burial depths of radioactiveparticles).4. A comparison of the 2009 swath and 2002 single-beam surveys suggested somechanges in the position of gross features but the significant difference in coverage(~100% vs.

SSEM/2011/4730 June 2011Appendix 3Currents at the Sellafield Pipeline: June 2010 –February 2011© Nuclear Decommissioning Authority 2011.

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Cefas contract report C3629CCurrents at theSellafield pipeline:June 2010 – February 2011Authors: Tony Dolphin, Jon Rees, Peter KershawIssue date: 26 May, 2011

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–contacts:tony.dolphin@cefas.co.ukpeter.kershaw@cefas.co.ukHead officeCentre for Environment, Fisheries & Aquaculture SciencePakefield Road, Lowestoft, Suffolk NR33 0HT, UKTel +44 (0) 1502 56 2244 Fax +44 (0) 1502 51 3865www.cefas.co.ukCefas is an executive agency of Defra–

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Table of contents1 Introduction ................................................................................................................................... 1 2 Methods .......................................................................................................................................... 4 3 Results ......................................................................................................................................... 13 4 Discussion ................................................................................................................................... 42 –

56References ................................................................................................................................... 50Annex ........................................................................................................................................... 52Table of figures convention for currents is ‘direction to’, and the convention for waves is ‘directionfrom’. –

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Bed shear stress exceedance - Sellafield Pipeline100% exceedance908070605040 Tau-w Tau-c Tau-cw Sellafield 125 micron 250 micron 500 micron1mm2mm4mm30201000.01 0.1 1 10Bed shear stress (N/m 2 ) –

Bed shear stress exceedance - Sellafield Pipeline100% exceedance101Tau-w Tau-c Tau-cw Sellafield 125 micron250 micron500 micron1mm 2mm 4mm0.10.010.01 0.1 1 10Bed shear stress (N/m 2 ) –

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Boon, J.D., 2004. Secrets of the Tide: Tide and Tidal Current analysis and Predictions,Storm surges and Sea Level Trends. Horwood Publishing, Chichester, U.K.212 pp.Dolphin, T.J., Rees, J.M., Kershaw, P., and Fernand, L., 2011. Analysis of Historical CurrentMeter Data. Cefas Report C3269B for the Sellafield Particle Work Programme,38 p.Hammond, T.M. and Collins, M.B., 1978. Flume studies of the response of various currentmeter rotor/propellers to combinations of unidirectional and oscillatory flow.Ocean Dynamics, 32 (2), 1616 – 7341.Howarth, M.J., 2006. Hydrography of the Irish Sea: SEA6 Technical Report. POL InternalDocument 174, 30 p.Kershaw, P.J., Aldridge, J.N., van der Molen, J., Huntley, D.A., Rees, J.M., and Mason, C.,2009. Sellafield Particle Work Programme, Work Stream 3: Transport andDispersion Model Development. Cefas report for the Environment Agency, 104p.Lee, G, Dade, W.B., Friedrichs, C.T., and Vincent, C.E., 2004. Examination of referenceconcentration under waves and currents on the inner shelf. Journal ofGeophysical Research, 109, C02021, doi:10.1029/2002JC001707.Pugh, D.T., 2004. Changing Sea Levels: Effects of Tides, Weather and Climate. CambridgeUniversity Press, 265 pp.Sherwin, 1987. Measurements of current speed using an Aanderaa RCM4 current meter inthe presence of surface waves. Continental Shelf Research, 8 (2), 131 – 144.Soulsby, R.L., 1997. Dynamics of Marine Sands. Thomas Telford Ltd, London, 249p.–

Soulsby, R.L. and Whitehouse, R.J.S.W, 1997. Threshold of sediment motion in coastalenvironments. Proceedings of Pacific Coasts and Ports ’97 Conference,Christchurch, New Zealand, 1, 149 – 154.Vincent, M.A., Atkins, S.M., Lumb, C.M., Golding, N., Lieberknecht, L.M. and Webster, M.,2004. Marine nature conservation and sustainable development - the Irish SeaPilot. Report to Defra by the Joint Nature Conservation Committee,Peterborough.Young, E.F., Brown, J. and Aldridge, J.N., 2001. Application of a large area curvilinear modelto the study of the wind-forced dynamics of flows through the North Channel ofthe Irish Sea. Continental Shelf Research, 21, 1403 – 1434.–

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About usCefas is a multi-disciplinary scientific research andconsultancy centre providing a comprehensive rangeof services in fisheries management, environmentalmonitoring and assessment, and aquaculture to a largenumber of clients worldwide.We have more than 500 staff based in 2 laboratories,our own ocean-going research vessel, and over 100 yearsof fisheries experience.We have a long and successful track record indelivering high-quality services to clients in a confidentialand impartial manner.(www.cefas.co.uk)Cefas Technology Limited (CTL) is a wholly ownedsubsidiary of Cefas specialising in the application of Cefastechnology to specific customer needs in a cost-effectiveand focussed manner.CTL systems and services are developed by teams thatare experienced in fisheries, environmental managementand aquaculture, and in working closely with clients toensure that their needs are fully met.(www.cefastechnology.co.uk).Customer focusWith our unique facilities and our breadth of expertise inenvironmental and fisheries management, we can rapidly puttogether a multi-disciplinary team of experienced specialists,fully supported by our comprehensive in-house resources.Our existing customers are drawn from a broad spectrumwith wide ranging interests. Clients include:international and UK government departmentsthe European Commissionthe World BankFood and Agriculture Organisation of the United Nations(FAO)oil, water, chemical, pharmaceutical, agro-chemical,aggregate and marine industriesnon-governmental and environmental organisationsregulators and enforcement agencieslocal authorities and other public bodiesWe also work successfully in partnership with otherorganisations, operate in international consortia and haveseveral joint ventures commercialising our intellectualpropertyHead officeCentre for Environment, Fisheries & Aquaculture SciencePakefield Road, Lowestoft,Suffolk NR33 0HT UKCentre for Environment, Fisheries & Aquaculture ScienceBarrack Road, The NotheWeymouth, DT4 8UBTel +44 (0) 1502 56 2244 Tel +44 (0) 1305 206600Fax +44 (0) 1502 51 3865 Fax +44 (0) 1305 206601Web www.cefas.co.ukprinted on paper made froma minimum 75% de-inkedpost-consumer waste© Crown copyright 2011

SSEM/2011/4730 June 2011Appendix 4Modelling Gamma Spectrometry Systems for use inBeach Monitoring Near Sellafield© Nuclear Decommissioning Authority 2011.

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Modelling Gamma Spectrometry SystemsFor Use in Beach Monitoring Near SellafieldPart II:Effect of 137 Cs Background and Simulation of FindsA.J. Cresswell, D.C.W. Sanderson,June 2011Issue 1SUERC Report for Sellafield LtdContract # 4510249592

SummaryThe response of large volume Airborne Gamma Spectrometry (AGS) detectors has beenmodelled using Monte Carlo methods as part of an assessment of ways to enhancemonitoring of beaches and other coastal areas for radioactive particles. Airborne surveymethods are capable of rapid surveys of large areas, and of covering diverse environmentseffectively, including areas where ground based work is difficult to implement safely. Theyhave potential for increasing the effectiveness of ground based surveys, working in acomplementary manner to identify areas where detailed work including recovery operationswould be targeted. The study presented here is a continuation of an earlier study definingpoint source detection limits for airborne gamma spectrometry in natural radioactivitybackgrounds representative of the West Cumbria beaches. Here anthropogenic backgroundsin the area are also reviewed together with their impact on detection limits. Similarly thesignals that would be expected from particles already recovered from the beaches of WestCumbria are assessed in comparison with observed background for 137 Cs to appraise theextent to which those particles recovered may have contributed to past airborne surveys of thebeaches. Theoretical sensitivities have been assessed using airborne systems operated undertwo survey designs: a “rapid” design at 75 m (200 ft) ground clearance and a 70 knot (30 m s -1 )survey speed, capable of surveying > 60km of shore in a 2h survey with multiple lines; andalso a “slow and low” design based on 15 m (50 ft) ground clearance and 15 knot (5 ms -1 )forward velocity, suitable to surveys of ~5km of beach in a 2h flight. Additionalconsideration is given to surveys at further reduced height and speed, to meet a detectioncriterion of 10 5 Bq sources at 10cm burial depth.Monte-Carlo methods were used to simulate the full spectral responses for a series of 137 Csand 241 Am point sources placed in simulated natural background environments with varying137 Cs background distributions. The MCII Monte Carlo code developed at SUERC, whichhas been extensively validated in the past and incorporates statistical estimation procedures tosimulate spectra at airborne source-detector separations, was used.A review of the distribution of dispersed 137 Cs on the beaches showed areas of beach withnegligible 137 Cs activity, areas with approximately uniform 137 Cs backgrounds, and areas withpatches of dimensions of 5-10m with elevated 137 Cs activity. Samples collected from thehigher activity areas of the beaches had activity concentrations of ~50 Bq kg -1 . Spectra weresimulated for 137 Cs background distributions for single and multiple patches of activity with10m dimensions and 50 Bq kg -1 concentrations, and uniform distributions of differentconcentrations, at 75 and 15m heights. The analyses for point sources with the mediumnatural background conducted in the earlier study were repeated with these different 137 Csbackgrounds.The data for the location, depth and activity for the recovered particles were used to simulatethe spectra that an airborne system would observe from these particles, and compared withthe spectra recorded during earlier surveys of the beaches of West Cumbria. Each particlerecovered is below the detection limit of a 75m survey, and even cumulatively the recoveredfinds would not result in any observed signal in the past surveys. The past airborne surveydata show that there is a considerable 137 Cs inventory on the beaches (1.3TBq between StBees and Duddon), of which the recovered particles represent

The results have shown that in the presence of approximately uniform natural andanthropogenic background radiation fields typical for the sand and gravel beaches, “rapid”AGS surveys would have a detection limit for superficial 137 Cs sources of 5-10 MBq, andmore detailed “low and slow” surveys would have detection limits of 200-300 kBq. Detectionlimits for sources at 10cm burial are a factor of 4 greater. “Low and slow” surveys havedetection limits for superficial 241 Am of 1-2 MBq. The patches of activity simulated heregenerate almost identical flight line profiles as point sources of similar total activity. Atground level the smaller field of view compared with airborne systems assists suchdiscrimination for activity patches of the dimensions simulated here, although the sameambiguity would exist for smaller patches of dispersed activity. The use of collimation in theairborne system to reduce the field of view could be considered. A moderately dense patternof patches (eg: >25% of the area) approximates a uniform distribution of activity. In thissituation, detection limits for a uniform 137 Cs background of 50 Bq kg -1 are increased by asimilar factor to changing from a medium to high natural activity background.Reducing ground clearance would increase full energy peak count rates, by an order ofmagnitude at 5m compared to 15m. Thus surveys at these ground clearances wouldsignificantly increase the significance of full-energy peak counts from sources in comparisonwith the 15m specification. To achieve a detection limit for 137 Cs sources at 10cm depth of10 5 Bq in uniform background radiation fields it is estimated that it would be necessary toreduce ground speed to below 5 knots (2 m s -1 ) and ground clearance to 5-10m. A dataprocessing methodology that utilises the scattered part of the spectra (>80% of the total countrate from buried sources) might potentially further improve detection efficiency, and providean estimate of source burial depth. Detector collimation may allow better discriminationbetween point sources and small distributed patches of activity.The analysis here has related to detection of sources in single measurements, or summedconsecutive measurements treated as single measurements. In survey design and dataanalysis, observations are combined from multiple survey lines. Methods which utiliseinterpolation across several observations on multiple survey lines have the potential to lowerdetection limits compared to approaches that utilise information within single survey lines.However such analysis would be retrospective, which may have implications forimplementation in source searches.This work has confirmed that airborne methods are capable of providing useful levels ofsensitivity, with survey rates which can not be practically achieved at ground level. Airbornemethods can demonstrate the absence of strong sources within large areas whereanthropogenic background distributions are approximately uniform, and identify areas wherepatchy anthropogenic distributions would require further ground based investigations toconfirm the absence of sources. AGS has an important role in identifying where valuableground-based resources should be focussed. It is suggested that practical work be initiated toverify the theoretical detection limits presented here and that consideration be given todeveloping the AGS role in future programmes. In addition to validating the sensitivity anddetection limits demonstrated in this theoretical study, this would provide an opportunity toevaluate the practical limits for operating helicopters at low speed and ground clearance overpublic beaches while complying with safety and regulatory requirements.ii

Contents1. INTRODUCTION ................................................................................................................. 12. MODEL PARAMETERISATION ........................................................................................ 22.1 Background 137 Cs Activity Values ............................................................................... 22.2 Point Source Simulations ............................................................................................. 53. RESULTS .............................................................................................................................. 73.1 Uniform 137 Cs Background Simulations ...................................................................... 73.1.1 Static Measurements .......................................................................................... 73.1.2 Survey Line Profiles ........................................................................................ 133.2 Patches of Enhanced 137 Cs activity ............................................................................ 223.3 Simulation of Recovered Particles ............................................................................. 253.3.1 Simulation of Existing Survey Data ................................................................ 254. DISCUSSION ...................................................................................................................... 304.1 137 Cs backgrounds ...................................................................................................... 304.2 Response to recovered particles ................................................................................. 315. CONCLUSIONS.................................................................................................................. 33Acknowledgements .................................................................................................................. 34References ................................................................................................................................ 35Appendix A: Location and Activity Data for Recovered Particles .......................................... 36iii

List of FiguresFigure 2.1: Histogram of 137 Cs activity per unit area distribution for the coastline between StBees and the Duddon Estuary from the March 2000 survey, excluding salt marshes and directradiation from the Sellafield and Drigg sites. ............................................................................ 2Figure 2.2: Stripped 137 Cs count rate determined from June 2010 backpack survey. Theenhanced feature to the south east of the area is an area of vegetated beach. ........................... 4Figure 2.3: Ratio of counts in the 137 Cs window (IW) to counts above this window (AW), fordata collected by Nuvia Ltd from the beach at St Bees between May 2007 and October 2008..................................................................................................................................................... 5Figure 2.4: Depth distribution of recovered particles from the beaches in the Sellafield area. . 6Figure 3.1: Significance of count rates from superficial 137 Cs sources at 75m. ........................ 8Figure 3.2: Significance of count rates from buried 137 Cs sources at 75m. ............................... 9Figure 3.3: Significance of count rates from superficial 137 Cs sources at 15m. ...................... 10Figure 3.4: Significance of count rates from buried 137 Cs sources at 15m. ............................. 11Figure 3.5: Significance of count rates from superficial 241 Am sources at 15m...................... 12Figure 3.6: Profile plots showing the significance of measurements on a transect directly oversuperficial 137 Cs sources of 1MBq (black), 10MBq (blue) and 50MBq (red) under rapidsurvey conditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations. ..................................................................................................... 14Figure 3.7: Profile plots showing the significance of measurements for a transect 50m fromsuperficial 137 Cs sources of 1MBq (black), 10MBq (blue) and 50MBq (red) under rapidsurvey conditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations. ..................................................................................................... 15Figure 3.8: Profile plots showing the significance of measurements on a transect directly overburied 137 Cs sources of 10MBq (black), 50MBq (blue) and 100MBq (red) under rapid surveyconditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations. ..................................................................................................... 16Figure 3.9: Profile plots showing the significance of measurements for a transect 50m fromburied 137 Cs sources of 10MBq (black), 50MBq (blue) and 100MBq (red) under rapid surveyconditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations. ..................................................................................................... 17Figure 3.10: Profile plots showing the significance of measurements for a transect directlyover superficial 137 Cs sources of 0.1MBq (black), 0.5MBq (blue) and 1.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations. .............................................................................. 19Figure 3.11: Profile plots showing the significance of measurements for a transect directlyover buried 137 Cs sources of 0.5MBq (black), 1.0MBq (blue) and 2.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations. .............................................................................. 20Figure 3.12: Profile plots showing the significance of measurements for a transect directlyover superficial 241 Am sources of 1.0MBq (black), 5.0MBq (blue) and 10.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations. .............................................................................. 21Figure 3.13: Transects across a 10x10m patch of 137 Cs activity at 50 Bq kg -1 (black), asuperficial 2 MBq 137 Cs source (red) and a buried 7 MBq 137 Cs source (blue) at 75m (top) and15m (bottom) ground clearance. .............................................................................................. 23Figure 3.14: 137 Cs count rates for a transect across a chess-board pattern of 50 Bq kg -110x10m patches at 75m (top) and 15m (bottom) ground clearances. ...................................... 24iv

Figure 3.15: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for St Bees. ............ 26Figure 3.16: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for Seascale. .......... 27Figure 3.17: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for Drigg. .............. 28Figure 3.18: Average residual spectra for the beaches shown in figures 3.15-3.17. ............... 29List of TablesTable 2.1: Simulated depth of recovered particles ..................................................................... 6Table 3.1: Significance of single 9s measurements for transects across superficial 137 Cssources, for different 137 Cs background concentrations on the medium natural backgroundscenario, under rapid survey conditions................................................................................... 13Table 3.2: Significance of single 9s measurements centred on different sources in different137 Cs background concentrations for detailed survey parameters. ........................................... 18Table 4.1: Predicted detection limits for 137 Cs and 241 Am for the medium natural backgroundcondition and 50Bq kg -1 137 Cs uniform background. ............................................................... 31Table 4.2: 137 Cs activity on three beaches determined from the March 2000 airborne survey,and the total activity of particles recovered from these beaches. ............................................ 32Table A.1: Location and activities for particles recovered at Drigg ........................................ 36Table A.2: Location and activities for particles recovered at Seascale ................................... 37Table A.3: Location and activities for particles recovered at Sellafield .................................. 57Table A.4: Location and activities for particles recovered at Braystones ............................... 61Table A.5: Location and activities for particles recovered at St Bees ..................................... 63Table A.6: Location and activities for particles recovered north of St Bees ........................... 64v

1. INTRODUCTIONRecently, a number of small radioactive particles have been recovered from the beaches nearSellafield. A monitoring and recovery programme has been established using ground basedequipment, following the specification for the programme at Dounreay established by SEPA.Specifically, the ground based survey specification is to be able to locate 10 5 Bq activitysources at 10cm burial depths. The ground based approach is based on a slow movingvehicle, and as a result the area coverage in a single tide cycle is limited. This study aims tomodel the response of typical airborne systems to radioactive sources to quantify the potentialfor such systems to conduct much more rapid and extensive surveys of the beaches tocomplement the ground based approaches already in use.Airborne Gamma Spectrometry (AGS) is an established technique for rapidly measuring thedistribution of radionuclides in the environment. It is well suited to both wide area surveysand detailed surveys of smaller areas, especially where the speed of the method is importantin recording dynamic environments or where access from the ground is impracticable orpotentially hazardous. The method can easily map the distribution of activity on foreshoreswithin a single tidal cycle, including both beach areas easily accessible to ground basedmonitoring and boulder fields where access is more restricted. Within single tide cycles, adetailed airborne survey can therefore be used to locate the zones within wide coastal areaswhere ground based confirmation and recovery operations would be most effectivelydirected. Conversely it can demonstrate the absence of the most hazardous radioactiveparticles above detection limits in areas with a potential for receiving such materials frommarine pathways following storms or high tide events. Used together with appropriate groundbased support it could increase the effectiveness, efficiency and levels of public protection ofprogrammed work targeting the coastal zones near nuclear sites.The work reported here uses numerical modelling approaches to determine detection limitsfor 137 Cs and 241 Am point sources for airborne systems in environments containingbackground levels of dispersed 137 Cs activity, complementing an earlier stage of study whichinvestigated detection limits in a range of natural backgrounds (Sanderson & Cresswell2010). In addition, the radiation signals for the particulate finds recovered to date will besimulated for airborne survey systems. This simulated data set will be compared with existingAGS data to identify whether signals seen surveys in 1990 and 2000 (Sanderson et.al. 1990,2000) are consistent with particulate finds subsequently recovered.1

2. MODEL PARAMETERISATIONThe approach taken in this study to investigate the impact on detection limits of anybackground 137 Cs activity is similar to that used in the earlier phase of this study (Sanderson& Cresswell 2010). Data from surveys of the beaches in the vicinity of Sellafield have beenexamined to attempt to determine typical distributions of 137 Cs activity, which have then beenused to generate 137 Cs background spectra at ground clearances of 15m and 75m. The earlierreport describes the rationale for the selection of the beach material characteristics used in thesimulations and the selection of the code. The same parameters for the beach material areused in this work.In the earlier work, three natural background levels representative of the environment on thebeaches near Sellafield were used. The work presented here will describe the impact ondetection limits of 137 Cs backgrounds relative to the medium level background from thatwork.2.1 Background 137 Cs Activity Values137 Cs backgrounds that are representative of the range of the beaches in the vicinity of theSellafield site where particulate activity may be present have been selected by examination ofsurvey data from the beaches. The data used were collected by SUERC using airbornesurveys in 1990 and 2000 (Sanderson et.al. 1990, 2000), backpack systems comprising 3x3”NaI(Tl) detectors with digital spectral processing and integrated GPS (Cresswell et.al. 2010)and Nuvia Ltd using the Groundhog systems.The airborne surveys conducted by SUERC show 137 Cs activity along the beaches of WestCumbria. Figure 2.1 shows the frequency distribution of 137 Cs activity per unit area for thesection of coast between St Bees and the Duddon Estuary, excluding the salt marshenvironments and sections where the radiation signal included direct shine from the Sellafieldsite and the Drigg waste repository. The mean activity per unit area determined in the March2000 survey was 17.4 kBq m -2 , with a total 137 Cs activity of 1.3TBq.2520Frequency (%)1510500 10 20 30 40 50137 Cs kBq m -2Figure 2.1: Histogram of 137 Cs activity per unit area distribution for the coastline between StBees and the Duddon Estuary from the March 2000 survey, excluding salt marshes and directradiation from the Sellafield and Drigg sites.2

In June 2010, a brief exploratory investigation of a section of beach between St Bees andNethertown was conducted by SUERC using a pair of 3x3” NaI(Tl) spectrometers (Cresswellet.al. 2010). The survey targeted an area where anomalous 137 Cs activity had been noted on apebble beach in March 2000 during an airborne survey of West Cumbria (Sanderson et.al.2000). The count rate for a 137 Cs window was determined by stripping interferences from 40 K,238 U series and 232 Tl series isotopes, and is shown in figure 2.2. It can be seen that there arepatches of enhanced 137 Cs activity distributed across the beach, each patch having dimensionsof ~5m. Soil samples were collected from several of these patches and analysed in thelaboratory at SUERC, giving activity concentrations of ~50Bq kg -1 (dry weight). A patch ofvegetated sand had higher activity concentrations of ~100 Bq kg -1 (dry weight).Data from the Groundhog surveys conducted by Nuvia Ltd has been made available toSUERC for this study. This data consists of counts for 1s measurements in each of fiveNaI(Tl) detectors within three windows; a 137 Cs window (531-760 keV) and counts aboveand below this window. Full spectral data was not available. To yield an estimate of 137 Csdistribution the average count rate for the five detectors in each window was determined foreach 1s measurement and the ratio of the count rate within the 137 Cs window to the count rateabove this window was determined. Assuming no significant variations in the relativeconcentrations of the natural series activity on the beach, variations in this ratio will reflectvariations in 137 Cs distribution. Figure 2.3 shows this ratio plotted for surveys of the beach atSt Bees in May 2007, September 2007, April 2008 and October 2008, excludingmeasurements that included particulate finds. It can be seen that there are areas where theratio is enhanced relative to the general area, with the enhancements comprising individualpatches of ~10m dimension and areas where there are several such patches in closeproximity. Some of the patches appear to cluster around approximately linear bands. Thelarger areas of large numbers of patches of enhanced activity would approximate to uniformdistributions within the field of view of an airborne detector. Estimates of the activityconcentrations these patches of enhanced ratio might represent have not been made. Gammaspectrometry measurements of sands from the west Cumbrian beaches over many yearsconducted by Sellafield Ltd as part of wider environmental monitoring programmes haveshown 137 Cs concentrations of typically ~50 Bq kg -1 (Parker 2010, Desmond 2011), with adownward activity trend.The closely packed groups of enhanced activity clusters approximate to a laterally uniformdistribution. Thus, a set of backgrounds consisting of laterally uniform 137 Cs activity wasdefined corresponding to the detector field of view 100% filled with patches, 50% filled and25% filled. These would have uniform depth distributions of 137 Cs activity concentrations of50, 25 and 12.5 Bq kg -1 respectively. It is noted that a uniform 50 Bq kg -1 distribution wouldcorrespond to a 24 kBq m -2 activity per unit area (assuming 1600 kg m -3 density). The datafrom the coastal survey conducted in March 2000 (Sanderson et.al. 2000) showed somesections of beach with elevated 137 Cs activity concentrations to a maximum of ~25 kBq m -2which is consistent with the maximum concentration for the uniform activity distributionsthat will be considered here.An additional set of simulations of the 137 Cs background have been conducted for singleclusters of enhanced activity in an environment otherwise void of 137 Cs activity, and arepresented in this report. These are compared with the simulations of point sources conductedin the early part of this work, to determine the extent to which these patches might bemisidentified as particulates by an airborne survey.3

Figure 2.2: Stripped 137 Cs count rate determined from June 2010 backpack survey. Theenhanced feature to the south east of the area is an area of vegetated beach.4

Figure 2.3: Ratio of counts in the 137 Cs window (IW) to counts above this window (AW), fordata collected by Nuvia Ltd from the beach at St Bees between May 2007 and October 2008.2.2 Point Source SimulationsData specifying the date, location, depth and activity of all finds to date was supplied for usein this project. These data are tabulated in Appendix A. The distribution of the depths atwhich the finds have been recovered is shown in Figure 2.4. It can be seen that there are veryfew finds recovered from below 20cm depth, with the majority being recovered from the top10cm of the beach. Simulations of sources at depths that reasonably approximate therecovered finds are needed to simulate the response of the airborne detector to such sources.The first stage of this work simulated sources on the surface and at 10cm depth. In this stageof the work additional simulated spectra have also been produced for depths of 5cm, 15cmand 20cm, with the simulations for each range of recovered depth as given in Table 2.1.5

200150Number of finds1005000 5 10 15 20 25 30Depth (cm)Figure 2.4: Depth distribution of recovered particles from the beaches in the Sellafield area.Depth Range Simulated Depth Depth Range Simulated Depth0-2.5 cm 0 cm 12.5-17.5 cm 15 cm2.5-7.5 cm 5 cm >17.5 cm 20 cm7.5-12.5 cm 10 cmTable 2.1: Simulated depth of recovered particles6

3. RESULTS3.1 Uniform 137 Cs Background Simulations3.1.1 Static MeasurementsThe simulated source spectra for superficial 241 Am and 137 Cs, and 137 Cs at 10cm depth, for thedetector immediately above the source at 15m and 75m ground clearances generated in thefirst stage of this work have been used to model the effect of varying 137 Cs background, in ananalogous manner to the first stage work. The full-energy peak count rates for differentsource activities and integration times were determined, and the significance of these definedas the ratio of count rate to uncertainty calculated. The background count rate uncertainty istaken for a background measurement of equal duration as the measurement over the source,although a time averaged background would have reduced uncertainty in a uniformbackground environment.Figures 3.1-3.5 show the significance of the full-energy peak count rates for the 137 Cs and241 Am sources as a function of integration time, for the medium natural background scenarioin the first stage of the work and for that background enhanced by uniform 137 Cs backgroundactivities of 12.5, 25 and 50 Bq kg -1 . The dashed lines indicate a significance of 2,corresponding to a net signal with twice the uncertainty for single measurements.It can be seen that as the 137 Cs background activity increases, the significance ofmeasurements from sources in that environment decreases as would be expected. Thereduction in significance from no background to the 50 Bq kg -1 background is approximately1 in all cases, which is similar to the reduction in significance observed in the first stage ofthis work for a change from the medium to high natural background.7

1000 Bq kg -1SignificanceSignificanceSignificanceSignificance1010.10.011010.10.011010.10.011010.112.5 Bq kg -140 MBq20 MBq10 MBq5 MBq40 MBq20 MBq10 MBq25 Bq kg -15 MBq40 MBq20 MBq10 MBq5 MBq50 Bq kg -140 MBq20 MBq10 MBq5 MBq0.010 5 10 15 20 25 30Integration time (s)Figure 3.1: Significance of count rates from superficial 137 Cs sources at 75m.8

SignificanceSignificanceSignificance1010.10.0110.10.0110.10.010 Bq kg -112.5 Bq kg -120 MBq10 MBq5 MBq1 MBq20 MBq10 MBq5 MBq25 Bq kg -11 MBq20 MBq10 MBq5 MBq1 MBq50 Bq kg -1Significance10.120 MBq10 MBq5 MBq1 MBq0.010 5 10 15 20 25 30Integration time (s)Figure 3.2: Significance of count rates from buried 137 Cs sources at 75m.9

SignificanceSignificanceSignificanceSignificance1010.10.0110.10.0110.10.0110.10 Bq kg -11.0 MBq0.5 MBq0.2 MBq0.1 MBq12.5 Bq kg -11.0 MBq0.5 MBq0.2 MBq0.1 MBq25 Bq kg -1 1.0 MBq0.5 MBq0.2 MBq0.1 MBq50 Bq kg -1 1.0 MBq0.5 MBq0.2 MBq0.1 MBq0.010 5 10 15 20 25 30Integration time (s)Figure 3.3: Significance of count rates from superficial 137 Cs sources at 15m.10

100 Bq kg -14.0 MBqSignificanceSignificanceSignificanceSignificance10.110.110.112.0 MBq1.0 MBq0.5 MBq12.5 Bq kg -14.0 MBq2.0 MBq1.0 MBq0.5 MBq25 Bq kg -1 4.0 MBq2.0 MBq1.0 MBq0.5 MBq50 Bq kg -1 4.0 MBq2.0 MBq1.0 MBq0.5 MBq0.10 5 10 15 20 25 30Integration time (s)Figure 3.4: Significance of count rates from buried 137 Cs sources at 15m.11

0 Bq kg -1SignificanceSignificanceSignificance1010.11010.11010.18 MBq4 MBq2 MBq1 MBq12.5 Bq kg -18 MBq4 MBq2 MBq1 MBq25 Bq kg -1 8 MBq4 MBq2 MBq1 MBq50 Bq kg -1Significance1018 MBq4 MBq2 MBq1 MBq0.10 5 10 15 20 25 30Integration time (s)Figure 3.5: Significance of count rates from superficial 241 Am sources at 15m.12

3.1.2 Survey Line Profiles3.1.2.1 Rapid Large Area SurveySurveys conducted at 200-250ft (60-75m) ground clearance and approximately 70 knots (130kph) ground speed are capable of rapidly surveying large areas. For mapping dispersedactivity it has been shown that line spacings of 250m are usually adequate to locate mostfeatures, and larger line spacings would be acceptable to allow larger areas to be surveyed ina given time (Sanderson et.al. 2001). For rapid survey of large areas for point sources, acloser line spacing would likely be required. For this work, such a survey is defined as 250ft(75m) ground clearance, 70 knots (30 m s -1 ) ground speed and 100m line spacing.Figures 3.6-3.9 show the significance of transects directly over superficial and buried 137 Cssources, and at 50m offset distances, for the modelled uniform 137 Cs backgrounds. Thetransects are for individual 1s measurements, and correspond to the similar figures for naturalbackground in the earlier work.It had been noted in relation to natural backgrounds that increased integration time reducesthe measurement uncertainty, with an integration time that approximates to the time taken tocross the dimensions of the radiation field from the source being optimal. For the 75m groundclearance survey, 90% of the signal is observed within 120m of the source giving an optimalintegration time of 8s at 70 knots. Table 3.1 gives the significance for 9s measurements oversuperficial 137 Cs sources of 1, 10 and 50 MBq in the medium natural activity background, anduniform 137 Cs backgrounds of 12.5, 25 and 50 Bq kg -1 . It can be seen that for a superficial10MBq 137 Cs source, the significance of a single 9s measurement exceeds 2.5, thus it can beconcluded that for rapid surveys at 200-250ft and 70 knot ground speed should readilyobserve 137 Cs sources of 5-10MBq at or near the surface.Source Activity 0 Bq kg -1 12.5 Bq kg -1 25 Bq kg -1 50 Bq kg -11MBq 0.55 0.47 0.42 0.355MBq 2.03 1.85 1.71 1.5010MBq 3.24 3.04 2.88 2.6250MBq 8.17 8.04 7.91 7.68Table 3.1: Significance of single 9s measurements for transects across superficial137 Cs sources, for different 137 Cs background concentrations on the mediumnatural background scenario, under rapid survey conditions.13

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-300 -200 -100 0 100 200 300Distance along transect (m)Figure 3.6: Profile plots showing the significance of measurements on a transect directlyover superficial 137 Cs sources of 1MBq (black), 10MBq (blue) and 50MBq (red) under rapidsurvey conditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations.14

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-200 -150 -100 -50 0 50 100 150 200Distance along transect (m)Figure 3.7: Profile plots showing the significance of measurements for a transect 50m fromsuperficial 137 Cs sources of 1MBq (black), 10MBq (blue) and 50MBq (red) under rapidsurvey conditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations.15

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-300 -200 -100 0 100 200 300Distance along transect (m)Figure 3.8: Profile plots showing the significance of measurements on a transect directlyover buried 137 Cs sources of 10MBq (black), 50MBq (blue) and 100MBq (red) under rapidsurvey conditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations.16

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-200 -150 -100 -50 0 50 100 150 200Distance along transect (m)Figure 3.9: Profile plots showing the significance of measurements for a transect 50m fromburied 137 Cs sources of 10MBq (black), 50MBq (blue) and 100MBq (red) under rapid surveyconditions, for the medium natural background scenario with increasing uniform 137 Csbackground concentrations.17

3.1.2.2 Detailed Small Area SurveyFor smaller areas, more detailed surveys are possible. These would be conducted at lowerground clearances where possible, and reduced speed and line spacing. For this work, asurvey speed of 15 knots (5 m s -1 ) and a line spacing of 20m has been used as detailed surveyparameters. This corresponds to the survey height and speed for the detailed beach surveyconducted in March 2000 (Sanderson et.al. 2000). This would be sufficient to cover a2kmx200m area of beach in a one hour survey.Figures 3.10-3.12 show the significance of transects across superficial and buried 137 Cs andsuperficial 241 Am sources for 1s measurements at 15m height. As noted, increased integrationtime reduces the measurement uncertainty with optimal integration time corresponding to thetime taken to cross a feature. At 15m ground clearance, 90% of the observed signal isobserved within 25m of the source, giving an optimal integration time of 10s at 15 knots.Table 3.2 gives the significance of 9s measurements for the different source activities anddepths and background conditions for figures 3.10-3.12. It can be seen that for these detailedsurvey parameters, the significance of single 9s measurements would exceed 2 for superficialsources of 200kBq ( 137 Cs) and 1.2MBq ( 241 Am) and buried 1.0MBq 137 Cs sources.The earlier work had shown that reducing ground clearance increases peak count rate, with137 Cs peak count rates at 10m twice those at 15m and at 5m the count rate increases by afactor of 10. Thus, detection limits for very low surveys conducted at even slower speedswould be lower than these.SourceDepth137 Csbackground137 Cs0.1 MBq137 Cs0.2 MBq137 Cs0.5 MBq137 Cs1.0 MBq137 Cs2.0 MBqSurface 0 Bq kg -1 1.49 2.64 5.14 8.0012.5 Bq kg -1 1.36 2.45 4.92 7.7825 Bq kg -1 1.26 2.30 4.72 7.5850 Bq kg -1 1.11 2.07 4.38 7.22Buried 0 Bq kg -1 0.40 0.77 1.73 3.03 4.9912.5 Bq kg -1 0.36 0.69 1.59 2.83 4.7625 Bq kg -1 0.33 0.64 1.48 2.67 4.5750 Bq kg -1 0.28 0.55 1.31 2.41 4.23241 Am241 Am241 Am241 Am10 MBq1 MBq 1.2 MBq 5 MBqSurface 0 Bq kg -1 1.95 2.31 7.78 12.9112.5 Bq kg -1 1.89 2.24 7.64 12.7525 Bq kg -1 1.84 2.18 7.50 12.5950 Bq kg -1 1.75 2.08 7.25 12.28Table 3.2: Significance of single 9s measurements centred on different sources indifferent 137 Cs background concentrations for detailed survey parameters.18

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-80 -60 -40 -20 0 20 40 60 80Distance along transect (m)Figure 3.10: Profile plots showing the significance of measurements for a transect directlyover superficial 137 Cs sources of 0.1MBq (black), 0.5MBq (blue) and 1.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations.19

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-80 -60 -40 -20 0 20 40 60 80Distance along transect (m)Figure 3.11: Profile plots showing the significance of measurements for a transect directlyover buried 137 Cs sources of 0.5MBq (black), 1.0MBq (blue) and 2.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations.20

40 Bq kg -13Significance21012.5 Bq kg -13Significance21025 Bq kg -13Significance21050 Bq kg -13Significance210-80 -60 -40 -20 0 20 40 60 80Distance along transect (m)Figure 3.12: Profile plots showing the significance of measurements for a transect directlyover superficial 241 Am sources of 1.0MBq (black), 5.0MBq (blue) and 10.0MBq (red) underdetailed survey conditions, for the medium natural background scenario with increasinguniform 137 Cs background concentrations.21

3.2 Patches of Enhanced 137 Cs activityAs has been noted, the ground surveys conducted by Nuvia Ltd and SUERC observed smallpatches with enhanced 137 Cs activity of dimensions

0.80.6Count Rate0.40.20.0-200 -100 0 100 20035Distance (m)3025Count Rate20151050-100 -50 0 50 100Distance (m)Figure 3.13: Transects across a 10x10m patch of 137 Cs activity at 50 Bq kg -1 (black), asuperficial 2 MBq 137 Cs source (red) and a buried 7 MBq 137 Cs source (blue) at 75m (top) and15m (bottom) ground clearance.23

3020Stripped cps100-100 200 400 600 800 1000 1200Distance (m)10080Stripped cps6040200-200 200 400 600 800 1000 1200Distance (m)Figure 3.14: 137 Cs count rates for a transect across a chess-board pattern of 50 Bq kg -110x10m patches at 75m (top) and 15m (bottom) ground clearances.24

3.3 Simulation of Recovered Particles3.3.1 Simulation of Existing Survey DataData from existing surveys of the Cumbrian coastline in 1990 and 2000 (Sanderson et.al.1990, 2000) have been used to assess the 137 Cs contribution to these data, and determine howmuch of that contribution can be attributed to the particles recovered from the beaches. Theconcentrations of naturally occurring 238 U, 232 Th and 40 K were determined from the surveydata, and a simulated natural background determined for each measurement location byscaling the unit concentration background spectra.The position, depth and activity of each source recovered have been tabulated. Each spectrumin the simulated survey has been divided into 500ms sections, and the midpoint of eachsection determined. For any sources within a range of 220m, the spectrum this would producein a 500ms measurement is determined by scaling the simulated spectrum for therepresentative depth (from table 2.1) at that offset scaled by the source activity. The sourcespectra across the entire measurement are then summed to produce 137 Cs spectra due to thepoint sources recovered for the simulated survey.The simulated natural and 137 Cs spectra are then combined to produce a survey data set thatwould be expected if the recovered finds are the only source of 137 Cs in the environment. Inaddition, subtracting the simulated natural spectra from the measured spectra leave a residualspectrum containing other spectral components not accounted for by the natural seriessimulation.For the 75m simulated data set, all of the particles recovered from the beaches are below thedetection limits of the system. And, even the cumulative signal from all the sources wouldnot generate a signal in the detector. It is noted that the March 2000 coastline survey wasconducted at a ground clearance of typically 40-50m. The simulated data for 15m groundclearance were also used to determine whether a lower ground clearance, at the speed andline spacing of the coastline survey, would result in a measurable signal from the sourcesrecovered. This analysis also produced no signal in the simulated spectra from the sources.Figures 3.15-3.17 show the count rates in the 137 Cs window of the residual spectrum, formedby subtracting the simulated natural spectra from the measurements, for the beaches at StBees, Seascale and Drigg. The measured data for these are taken from the March 2000 surveyin the DEFRA study, and the 137 Cs activity per unit area determined in 2000 are also shownalong with the locations of the particles recovered from these beaches. The average residualspectra for these beaches, clearly showing the 662keV peak from 137 Cs, are shown in figure3.18. Clearly, these beach environments contain 137 Cs activity, but that the particles recoveredto date do not appear to contribute significantly to the observed spectra.25

Figure 3.15: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for St Bees.26

Figure 3.16: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for Seascale.27

Figure 3.17: 137 Cs activity concentration from the March 2000 coastline survey, and residual137 Cs count rates following subtraction of the simulated natural spectra, for Drigg.28

40St Bees30Residual cps2010040Seascale30Residual cps201003530Drigg25Residual cps20151050-50 500 1000 1500 2000 2500 3000Energy (keV)Figure 3.18: Average residual spectra for the beaches shown in figures 3.15-3.17.29

4. DISCUSSIONThe work reported here consists of two aspects related to airborne survey detection ofradioactive particles on the beaches around Sellafield, as a continuation of an earlier phase ofwork (Sanderson & Cresswell 2010). The earlier work used Monte Carlo simulationapproaches to determine detection limits for different survey parameters in natural radiationenvironments typical of the West Cumbrian coastline. The work reported here presentsassessments of the impact of dispersed 137 Cs backgrounds on detection limits, and theresponse to the particles already recovered from the beaches.4.1 137 Cs backgroundsPrevious airborne and ground based surveys have demonstrated that there are, in severalplaces, background levels of 137 Cs along the coastline of West Cumbria. On estuarine saltmarshes, where fine silt particles which readily sorb 137 Cs accumulate these backgroundlevels are very high. On sand and gravel beaches it is not expected that the 137 Cs containingsilts would accumulate, and background levels here are much lower. In some locations, inparticular in the vicinity of the Sellafield and Drigg sites, radiation originating from areasbehind the beach is a significant contribution to the 137 Cs background observed from anairborne survey.Detailed ground based surveys of the beaches of West Cumbria have shown that 137 Cs hasaccumulated in patches of several metre dimensions, and samples from these have typicallyshown activity concentrations of up to 50 Bq kg -1 . The form of the 137 Cs contamination isunknown, as is the depth profile of these patches of activity. For the purpose of this study, thedepth profile was assumed to be uniform to 30cm. The impact on detection limits forindividual patches of activity with concentrations of 50 Bq kg -1 , and areas where several suchpatches are present, have been determined along with uniform activity distributions.For activity distributions with uniform concentrations over areas that exceed 3-4 times thefield of view of the detector, and high density of patches of activity over similar areas, thelimits of detection for 137 Cs particles is only slightly increased by approximately the sameamount as observed in the previous phase of work with the change from a medium to highnatural background. The significance, defined as the ratio of net counts to the uncertainty, ofmeasurements over sources of different strengths and distributions have been calculated.Interpolation from these calculated values allows detection limits based on a significance ofeither 2 or 3 to be determined. This has been done for three survey parameters; a “rapid”survey at 75m ground clearance and 75 knots, a “low and slow” survey at 15m groundclearance and 15 knots, and a very slow survey at 15m and 4 knots. These are given in Table4.1 for the medium natural background and the highest 137 Cs background considered here.The earlier work noted that reducing the ground clearance below 15m would significantlyincrease full energy peak count rates, with a corresponding reduction in detection limits,although the full simulation of the spectra for these heights have not been conducted. Thesedetection limits assume a data analysis algorithm that can determine trends in the radiationsignal over time, such as the background change alarm criteria based on predicted signalsused by Nuvia or the filtered differential analysis approach (Cresswell & Sanderson 2009), orspatially using multiple measurements from different survey lines.For individual patches of activity of dimensions simulated here, the radiation observed from alow flying aircraft is indistinguishable from a single particle of similar total activity near the30

surface. This is a direct consequence of the relatively large field of view of the airbornesystem compared to the dimensions of the patch. Ground based approaches, with significantlysmaller fields of view for the detectors, are better able to distinguish signals from extendedpatches of background activity with these dimensions and discrete particles, although asimilar ambiguity between discrete sources and dispersed activity would still exist for smallerpatches. The use of collimated detectors or self-collimated detector arrays in airborne surveycould be considered to improve the ability of such systems to identify discrete particles inenvironments with patches of enhanced activity.With several patches of activity in a given area, an intermediate situation exists where for lowdensities of patches the problems of distinguishing between a patch of activity and a sourcedominates, and at higher densities of patches the environment approaches one where the 137 Csbackground is uniform.SourceSuperficial137 CsBuried137 CsSuperficial241 Am137 CsBackgroundDetection Limit (MBq)Rapid Survey Low and Slow 4 knots3σ 2σ 3σ 2σ 3σ 2σ0 Bq kg -1 9 5 0.23 0.14 0.050 0.03050 Bq kg -1 10 6 0.28 0.17 0.065 0.0370 Bq kg -1 35 20 1.00 0.60 0.22 0.1450 Bq kg -1 39 23 1.20 0.75 0.29 0.170 Bq kg -1 n/d n/d 1.5 1.0 0.35 0.2250 Bq kg -1 n/d n/d 2.0 1.3 0.45 0.30Table 4.1: Predicted detection limits for 137 Cs and 241 Am for the medium naturalbackground condition and 50Bq kg -1 137 Cs uniform background.4.2 Response to recovered particlesThe March 2000 coastline survey flight has been recreated for the section between St Beesand Duddon, by generating natural series spectra from the simulations conducted in the firstphase of this work scaled by the measured activity concentrations and simulated spectra forthe sources recovered from the beaches. For both 75m and 15m ground clearance data alongthe flight lines of the March 2000 survey, the recovered sources contribute no counts to thespectra. The recovered particles are all below detection limits for the 75m survey, and eventhe cumulative spectrum from several sources is below detection limit. A few (3) of therecovered sources have activities above 200kBq and were recovered from the top 10cm of thebeach. These particles were all recovered from the Sellafield foreshore. These should bedetectable using a slow survey at 15knots or less and 15m ground clearance, especially withclose linespacing. A few more (2-3) may have been detectable under such detailed surveyconditions. The survey flights in March 2000 were too fast, too high and too far apart toobserve them.Residual spectra have been produced by subtracting the simulated natural spectra from themeasured spectra for the March 2000 survey. The count rates within a window around the137 Cs peak in these spectra have been mapped for sections of beach at St Bees, Seascale andDrigg. These show distributions that correspond reasonably well to the 137 Cs activity per unitarea determined in March 2000, although there are some differences in the spatial31

distribution. There appears to be no obvious strong correlation between the areas of enhanced137 Cs signal and the locations where particles were recovered.The March 2000 survey data have also been regridded to allow inventory analysis for thebeaches along the West Cumbrian coasts, following the procedure developed in the DETRled work (Sanderson et.al. 2001, 2007). Table 4.2 lists the total 137 Cs activity determinedfrom the airborne survey data for the beaches at St Bees, Seascale and Drigg, along with thetotal activity for the particles recovered from those beaches. For St Bees and Seascale, theNuvia surveys have covered almost 50% of the beach area, the coverage for Drigg issignificantly lower than this. Thus, it can be assumed that the total activity for recoverableparticles on these beaches will be higher than that given in Table 4.2. It can be seen that theparticles recovered constitute a very tiny fraction of the total 137 Cs activity on these beaches(less than 0.001%). As noted previously, the form and distribution of the majority of theactivity on these beaches is at present unknown.LocationTotal 137 Cs ActivityAGSFindsSt Bees 32.7 ± 0.1 GBq 101 kBqSeascale 217.8 ± 0.2 GBq 300 kBqDrigg 230.2 ± 0.3 GBq 89 kBqTable 4.2: 137 Cs activity on three beaches determined from the March 2000airborne survey, and the total activity of particles recovered from these beaches.32

5. CONCLUSIONSAn earlier study on the detection limits of airborne survey methods to radioactive particles onbeaches in West Cumbria has been extended to investigate the impact of dispersed 137 Csbackground activity on detection limits. Spectra for airborne survey detectors at 75m and15m ground clearance have been simulated for 137 Cs activities in uniform distribution, and forpatches of activity of 10m dimension. These have been added to the existing natural seriessimulations for medium natural background concentrations.It has been shown that where that activity is dispersed in an approximately uniform mannerover areas several times the detector field of view the impact on detection limits is small. For137 Cs activity concentrations of 50 Bq kg -1 corresponding to the increase in detection limitsfor both 137 Cs and 241 Am particles observed by changing from a medium to high naturalactivity background. In a medium natural background environment with no 137 Cs backgroundfor a “low and slow” survey at 15m ground clearance and 15 knot (5 m s -1 ) ground speed,single measurement 2σ detection limits for 137 Cs sources at 10cm depth of ~6.0x10 5 Bq hadbeen estimated in the previous work, a uniform 137 Cs background of 50 Bq kg -1 wouldincrease detection limits at this depth to ~7.5x10 5 Bq. The 241 Am detection limit forsuperficial sources would increase from ~1.0x10 6 Bq to ~1.3x10 6 Bq, although it should benoted that the detector response to 241 Am energies would be highly dependent upon thegeochemistry of the soil matrix. Reducing ground speed to below 5 knots would reducedetection limits for buried 137 Cs sources to ~2.0x10 5 Bq.For individual 10m patches of activity, these are indistinguishable from discrete 137 Cs pointsources of similar total activity (~2MBq for a 50 Bq kg -1 concentration) using the full energypeak count rate from uncollimated airborne detectors. In areas where such patches of activitycluster, the radiation fields from each patch overlap to generate a radiation field thatapproximates to a uniform activity distribution. A patchy 137 Cs distribution would result in anincrease in detection limits for 137 Cs particles of at most an order of magnitude compared to auniform distribution, dependent upon the density of patches and the activity concentrationwithin each patch. For 241 Am, the detection limit for patchy and uniform activity would besimilar, for a given activity concentration, assuming the spectral processing correctlyaccounts for the soil geochemistry.Previous airborne surveys of West Cumbria in 1990 and 2000 showed the presence of 137 Cson, or near, the beaches north and south of Sellafield. These surveys were conducted atspeeds and ground clearances where detection limits would be 1-5MBq, larger than anyindividual particle recovered from these beaches. A simulation of the response of airbornesystems to all the particles recovered from the beaches of West Cumbria has shown that thesefinds, even cumulatively, did not contribute to the activity observed. Less than 0.001% of theactivity on the beaches calculated from the airborne surveys can be attributed to the recoveredparticles.The work conducted in the two phases of this investigation has shown that the variations innatural and anthropogenic background on the beaches of West Cumbria do not preclude theuse of airborne and other radiometric methods in collecting data at levels of sensitivityrelevant to locating radioactive particles. AGS methods can be used to survey large areas,demonstrate the absence of radioactive particles above 5-10 MBq of 137 Cs and identify areaswhere apparent patchy 137 Cs background would require detailed ground based follow-up toconfirm the absence of any particulates. More detailed surveys at reduced speed and ground33

clearance reduce detection limits, with area survey rates of ~0.5 km 2 h -1 at 50 ft groundclearance or lower being able to demonstrate the absence of 137 Cs sources of 10 5 -10 6 Bq.AGS methods allow work at rates which permit changes over single tidal cycles to beeffectively monitored, and to register signals from areas which would be difficult to accesswith vehicular based approaches. It is therefore concluded that AGS methods could beincorporated into programmes for assuring the environmental quality of coastal zones in thevicinity of nuclear sites. Further review of the form and distribution of the dispersed 137 Csactivity on the beaches and investigation of approaches to detector collimation to betterdistinguish between point and dispersed activity may be helpful.Survey design is an important consideration in particle detection. It has been demonstratedhere that to ensure detection limits below 10 5 Bq an airborne survey would need to beconducted at a very low ground clearance (

ReferencesCresswell, A.J., Sanderson, D.C.W, (2009). The use of difference spectra with a filtered rollingaverage background in mobile gamma spectrometry measurements. Nuclear Instruments and MethodsA607, 685-694.Cresswell, A.J., Sanderson, D.C.W., Maneuski, D. (2010). Mobile Gamma SpectrometryMeasurements of Coneyside Beach, Cumbria. SUERC Report. Available athttp://eprints.gla.ac.uk/45771/Desmond, J.A. (2011). Pers. Comm.Parker, T. (2010). Pers. Comm.Sanderson, D.C.W., Allyson, J.D., Cairns, K.J, MacDonald, P.A. (1990). A Brief AerialSurvey in the Vicinity of Sellafield in September 1990. SURRC Report for BNFL.Sanderson, D.C.W., Cresswell, A.J., Murphy, S. (2000). Investigation of Spatial andTemporal Aspects of Airborne Gamma Spectrometry: Preliminary Report on Phase II Surveyof the Sellafield Vicinity, the Former RAF Carlisle Site, the Albright and Wilson Plant,Workington Harbour and the Cumbrian Coastline Conducted March 2000. SURRC Reportfor DETR, Project Ref: RW 8/6/80.Sanderson, D.C.W., Cresswell, A.J., White, D.C., Murphy, S., McLeod, J. (2001).Investigation of Spatial and Temporal Aspects of Airborne Gamma Spectrometry: FinalReport. SURRC Report for DETR, Project Ref: RW 8/6/80.Sanderson, D.C.W., Cresswell, A.J., White, D.C. (2007). The effect of flight line spacing onradioactivity inventory and spatial feature characteristics of airborne gamma-rayspectrometry data. International Journal of Remote Sensing 29, 31-46.Sanderson, D.C.W., Cresswell, A.J. (2010), Modelling Gamma Spectrometry Systems for usein Beach Monitoring near Sellafield. SUERC report for Sellafield Ltd, contract no.4510249592.35

Appendix A: Location and Activity Data for Recovered ParticlesPosition (BNG)Activity of recovered particle (Bq)Date x y d (cm) Substrate137 Cs241 Am60 Co19/10/2007 304627 498332 12 sand 3991 7822/10/2007 304880 497961 3 sand 22 5360022/10/2007 304880 497961 3 sand 19 2650023/10/2007 304477 498289 10 sand 90 4480 865023/10/2007 304517 498250 7 sand 32200 21827/05/2008 305990 495968 5 sand 52405 32327/05/2008 306058 465892 1 sand 22 5750016/06/2010 306397 495911 1 Sand 29 3220022/06/2010 305024 497826 3 Sand 30 4810006/07/2010 305001 497629 2 Sand 28 3750012/07/2010 304991 498045 2 Sand 25 2520014/07/2010 304651 497535 1 Sand 27 2820014/07/2010 305045 497346 3 Sand 23 2990015/07/2010 306891 495177 2 Sand 23 2660015/07/2010 306797 495289 2 Sand 44 760019/07/2010 307471 495339 1 Sand 26 2870021/07/2010 306690 494806 1 Sand 24 32900Table A.1: Location and activities for particles recovered at Drigg36

Position (BNG)Activity of recovered particle (Bq)Date x y d (cm) Substrate137 Cs241 Am60 Co05/06/2007 303014 501739 0 sand 82 133 645806/06/2007 302423 502028 5 sand 13901 15707/06/2007 303012 501244 0 sand 17202 17403/10/2007 303269 501100 10 sand 11400 13204/10/2007 303304 501144 3 sand 4370 26605/10/2007 303281 501134 7 sand 7912 10805/12/2007 304389 499512 3 shingle 5774 10421/04/2008 303575 500853 15 sand 34005 26223/04/2008 303543 500907 8 sand 9651 14409/05/2008 303344 501385 4 sand 37301 28510/11/2008 303506 500966 5 sand 18102 20412/11/2008 303272 501405 0 sand 25 2860013/11/2008 303500 501108 0 sand 26 8410013/11/2008 303145 501622 3 sand 6161 12217/11/2008 303048 501587 20 sand 24701 20918/11/2008 302692 501820 1 sand 25 7460018/11/2008 302706 501832 2 sand 14001 019/11/2008 302912 501872 2 sand 5311 11924/02/2009 302273 502023 28 sand 60203 71126/02/2009 302650 501967 5 sand 475 9111/05/2009 303563 500956 2 Sand 5290 21111/05/2009 303369 501150 3 Sand 3330 16914/05/2009 303285 501428 3 Sand 25 9800018/05/2009 302620 502210 2 Sand 5540 20211/06/2009 304107 500007 2 Sand 4240 17127/08/2009 302668 501850 8 Sand 3700 17501/09/2009 302764 501861 2 Sand 27 2840009/09/2009 303966 499906 6 Sand 2921 17111/09/2009 304025 499784 6 Sand 4392 20914/09/2009 304160 499614 0 Sand 28 1870020/03/2010 302954 501559 1 Sand 29 3740822/03/2010 302844 501993 1 Sand 31 2940624/03/2010 302870 501872 1 Sand 24 3210024/03/2010 302846 501720 1 Sand 24 3820027/03/2010 303229 501572 3 Sand 28 3000527/03/2010 302949 501587 2 Sand 25 2100427/03/2010 303172 501451 1 Sand 27 3170626/04/2010 303434 500987 1 Sand 26 2520230/04/2010 303249 500858 2 Sand 24 376011/05/2010 303485 501111 1 Sand 27 1450111/05/2010 303322 500950 2 Sand 21 2170212/05/2010 303266 500884 1 Sand 29 2090113/05/2010 303373 500960 2 Sand 22 3330217/05/2010 303387 501084 3 Sand 22 51702Table A.2: Location and activities for particles recovered at Seascale37

Position (BNG)Activity of recovered particle (Bq)Date x y d (cm) Substrate137 Cs241 Am60 Co29/11/2006 301605 503303 2 Sand 7465 53329/11/2006 301575 503341 12 Sand 2460030/11/2006 301841 503349 10 Shingle 767030/11/2006 301813 503501 0 Shingle 8530030/11/2006 301772 503354 8 Sand 4970001/12/2006 301843 503484 5 Shingle 5260001/12/2006 301556 503325 12 Sand 884001/12/2006 301562 503331 10 Sand 1640001/12/2006 301583 503308 0 Sand 1040024/05/2007 301649 503257 5 Sand 32111 30924/05/2007 301675 503274 15 Sand 68224 38824/05/2007 301750 503272 10 Sand 31613 25724/05/2007 301972 503145 10 Sand 11704 14824/05/2007 302029 503115 5 Sand 11904 15325/05/2007 302046 503073 1 Sand 21 35701025/05/2007 301582 503360 5 Sand 5482 10925/05/2007 301583 503359 10 Sand 7222 14725/05/2007 301614 503317 20 Sand 115041 49025/05/2007 301590 503316 7 Sand 12905 15225/05/2007 301588 503334 2 Sand 9864 13525/05/2007 301599 503340 2 Sand 17 9800325/05/2007 301716 503413 8 Sand 17807 17225/05/2007 301728 503425 17 Sand 30114 21225/05/2007 301758 503436 17 Sand 53926 28326/05/2007 302106 503043 10 Sand 30212 21826/05/2007 302146 502985 1 Sand 11505 13227/05/2007 302246 502870 2 Sand 12306 16927/05/2007 302240 502839 13 Sand/Shingle 191 114027/05/2007 302276 502859 1 Shingle 13007 16628/05/2007 302163 502987 3 Sand/Shingle 16208 18228/05/2007 302249 502924 0 Sand/Shingle 13807 19429/05/2007 302302 502738 10 Sand/Shingle 26812 25229/05/2007 302235 502815 13 Sand/Shingle 91 97130/05/2007 302140 502886 0 Sand/Shingle 10804 14030/05/2007 302195 502600 1 Sand/Shingle 11405 15131/05/2007 301464 503362 16 Sand 52619 32631/05/2007 301485 503429 5 Sand 5652 12331/05/2007 301678 503520 4 Sand 25910 22101/06/2007 301488 503424 2 Sand 6453 10101/06/2007 301530 503376 2 Sand 821 5801/06/2007 301590 503413 3 Sand 6513 30301/06/2007 301532 503413 8 Sand 8354 13138

01/06/2007 301643 503527 11 Sand 10606 13101/06/2007 301663 503514 2 Sand 30216 23301/06/2007 301717 503643 2 Sand 45925 22901/06/2007 301798 503540 2 Shingle 11006 14001/06/2007 301786 503566 1 Shingle 11207 16601/06/2007 301799 503545 1 Sand/Shingle 79048 46402/06/2007 301485 503423 2 Sand 5103 11102/06/2007 301476 503431 8 Sand 88658 41102/06/2007 301531 503357 3 Sand 19 5620302/06/2007 301531 503441 0 Sand 2872 9302/06/2007 301646 503504 3 Sand 62742 34702/06/2007 301692 503682 0 Sand 16711 19402/06/2007 301820 503506 4 Sand/Pebbles 60343 36903/06/2007 301611 503523 13 Sand/Pebbles 58342 36903/06/2007 301589 503557 0 Sand 6715 13103/06/2007 301604 503555 8 Sand 47034 32303/06/2007 301615 503564 8 Sand 17813 20703/06/2007 301624 503563 2 Sand 7607 13103/06/2007 301659 503629 0 Pebbles 67962 38503/06/2007 301695 503620 23 Sand 131120 37003/06/2007 301716 503630 0 Shingle 44941 28303/06/2007 301725 503651 0 Pebbles 68163 37304/09/2007 301660 503252 1 Sand 5661 11004/09/2007 301724 503244 15 Sand 52008 31404/09/2007 301780 503276 12 Sand 20803 20104/09/2007 301925 503312 0 Sand 5031 11205/09/2007 301607 503308 2 Sand 2740 8905/09/2007 301604 503360 5 Sand 6071 14505/09/2007 301699 503418 0 Sand 5761 10205/09/2007 301725 503405 9 Sand 15502 44406/09/2007 301720 503464 3 Sand 11903 13806/09/2007 301720 503468 7 Sand 16405 16606/09/2007 301735 503406 7 Sand 2480 25006/09/2007 301726 503444 4 Sand 2991 8706/09/2007 301731 503423 4 Sand 4361 52206/09/2007 301679 503504 5 Sand 2241 7206/09/2007 301682 503502 6 Sand 8423 12206/09/2007 301738 503426 3 Sand 7102 11306/09/2007 301730 503450 2 Sand 6592 11707/09/2007 301784 503487 5 Sand 10102 13007/09/2007 301809 503491 8 Sand 19 63400910/09/2007 301915 503310 5 Sand 17402 172 24210/09/2007 301662 503352 10 Sand 3731 28611/09/2007 301492 503445 5 Sand 10802 14039

11/09/2007 301521 503408 6 Sand 1950 14711/09/2007 301512 503436 3 Sand 2790 7811/09/2007 301703 503558 28 Sand 31805 21912/09/2007 301525 503414 12 Sand 7251 11012/09/2007 301517 503436 13 Sand 7311 10612/09/2007 301536 503428 9 Sand 7721 10712/09/2007 301543 503419 8 Sand 2850 7612/09/2007 301540 503426 6 Sand 2791 14212/09/2007 301677 503497 6 Sand 23 6520012/09/2007 301726 503577 5 Sand 6992 11813/09/2007 301540 503432 11 Sand 4571 10113/09/2007 301534 503478 3 Sand 3691 17113/09/2007 301534 503481 1 Sand 2321 7513/09/2007 301552 503431 5 Sand 19 5520013/09/2007 301554 503427 1 Sand 19 2560013/09/2007 301540 503470 5 Sand 6202 11713/09/2007 301559 503427 8 Sand 3851 9213/09/2007 301695 503493 2 Sand 11004 14013/09/2007 301637 503517 3 Sand 5872 28513/09/2007 301712 503519 7 Sand 9024 14314/09/2007 301507 503429 12 Sand 7183 12914/09/2007 301496 503444 5 Sand 2891 5414/09/2007 301494 503441 3 Sand 3852 12014/09/2007 301519 503413 3 Sand 4742 9614/09/2007 301570 503412 7 Sand 6243 12614/09/2007 301501 503421 12 Sand 4162 11514/09/2007 301488 503434 5 Sand 2801 8314/09/2007 301526 503387 0 Sand 4501 45614/09/2007 301491 503425 6 Sand 5092 15514/09/2007 301529 503384 10 Sand 33816 27614/09/2007 301512 503401 8 Sand 2631 9114/09/2007 301709 503428 0 Sand 18 1610014/09/2007 301718 503441 2 Sand 4782 11714/09/2007 301778 503504 2 Sand 18 2630007/11/2007 301581 503625 3 Sand 4640 9007/11/2007 301474 503743 0 Sand 2900 8207/11/2007 301508 503697 2 Sand 5901 5307/11/2007 301483 503717 6 Sand 23804 18507/11/2007 301588 503592 0 Sand 14801 96508/11/2007 301576 503753 2 Sand 11401 14308/11/2007 301590 503735 7 Sand 1160 5808/11/2007 301683 503691 2 Sand 18405 17308/11/2007 301617 503770 3 Sand 20806 18508/11/2007 301517 503870 3 Sand 22 7260040

08/11/2007 301498 503897 5 Sand 12003 14408/11/2007 301502 503889 4 Sand 14901 8008/11/2007 301504 503868 2 Sand 13104 14708/11/2007 301510 503860 6 Sand 8531 24609/11/2007 301626 503741 3 Sand 2141 6809/11/2007 301584 503783 4 Sand 7302 16009/11/2007 301664 503670 15 Sand 76326 32609/11/2007 301637 503711 0 Sand 10203 73609/11/2007 301600 503758 8 Sand 9393 13809/11/2007 301498 503931 10 Sand 12604 14012/11/2007 301502 503687 1 Sand 17 10100112/11/2007 301522 503638 5 Sand 13603 15312/11/2007 301427 503971 16 Sand 71934 33512/11/2007 301499 503940 10 Shingle 33908 5912/11/2007 301457 503974 0 Pebbles 8345 13512/11/2007 301484 503959 8 Pebbles 144 219 2346312/11/2007 301507 503939 15 Pebbles 177105 52112/11/2007 301508 503943 7 Pebbles 10206 6712/11/2007 301606 503833 6 Pebbles 31619 23212/11/2007 301582 503862 0 Pebbles 14509 16012/11/2007 301494 503977 5 Pebbles 44412 18212/11/2007 301596 503844 5 Pebbles 19713 19412/11/2007 301431 504013 3 Pebbles 20414 19213/11/2007 301469 503723 15 Sand 3432 8913/11/2007 301509 503688 6 Sand 4161 10413/11/2007 301492 503692 0 Sand 4651 13913/11/2007 301472 503715 0 Sand 18 3540013/11/2007 301516 503651 0 Sand 18 323013/11/2007 301584 503575 13 Sand 10602 14513/11/2007 301376 504048 3 Sand 18804 19513/11/2007 301402 504018 6 Sand 9306 12613/11/2007 301406 504022 4 Sand 28712 15713/11/2007 301414 504028 9 Pebbles 4723 9613/11/2007 301354 504127 15 Pebbles 63141 30013/11/2007 301341 504143 3 Pebbles 14510 14113/11/2007 301396 504101 14 Pebbles 67345 30013/11/2007 301354 504153 0 Pebbles 12308 14313/11/2007 301289 504228 10 Pebbles 5864 10313/11/2007 301289 504227 3 Pebbles 17715 17813/11/2007 301408 504066 8 Pebbles 22619 17413/11/2007 301285 504227 5 Pebbles 15814 14714/11/2007 301387 503556 10 Sand 59647 28814/11/2007 301424 503493 7 Sand 24321 19214/11/2007 301425 503490 5 Sand 12611 14441

14/11/2007 301442 503457 4 Sand 25522 19414/11/2007 301451 503443 2 Sand 6496 11514/11/2007 301450 503450 1 Sand 12712 15614/11/2007 301426 503498 2 Sand 4584 10414/11/2007 301457 503443 2 Sand 2062 13914/11/2007 301212 504112 1 Sand 20 5240114/11/2007 301247 504224 7 Sand 14414 19814/11/2007 301285 504170 10 Sand 11011 15015/11/2007 301065 504195 5 Sand 5092 63715/11/2007 301136 504089 17 Sand 110032 478015/11/2007 301070 504192 19 Sand 19819 19115/11/2007 301132 504107 9 Sand 9188 13415/11/2007 301167 504059 17 Sand 11611 10015/11/2007 301110 504157 4 Sand 131045 223015/11/2007 301118 504155 20 Sand 176172 58715/11/2007 301106 504174 10 Sand 24624 46415/11/2007 300981 504705 3 Sand 19319 18215/11/2007 300943 504607 5 Sand 3183 11119/11/2007 300659 504882 6 Sand 1852 7119/11/2007 300611 504980 5 Sand 18 8820119/11/2007 300594 504837 6 Sand 27125 6919/11/2007 300663 504962 5 Sand 18 526019/11/2007 300732 504921 6 Sand 7927 12019/11/2007 300784 504853 10 Sand 127 198 1791020/11/2007 300349 505431 0 Sand 5795 10620/11/2007 300689 504900 7 Sand 5525 5720/11/2007 301695 503546 4 Sand 8828 13220/11/2007 301208 504282 1 Shingle 19117 18520/11/2007 300929 504647 8 Sand 38535 26422/11/2007 301866 503409 8 Sand 59250 28822/11/2007 301836 503454 17 Sand 29925 20123/11/2007 301716 503551 26 Sand 157124 49226/11/2007 301698 503646 0 Sand 20 5210026/11/2007 301680 503628 1 Sand 14910 19326/11/2007 301682 503610 6 Sand 59439 31126/11/2007 301674 503602 0 Sand 21 1570026/11/2007 301658 503618 3 Sand 10807 13826/11/2007 301653 503622 3 Sand 4843 9128/11/2007 301699 503556 5 Sand 21412 19428/11/2007 301690 503583 7 Sand 13408 15628/11/2007 301719 503589 20 Sand 9566 13729/11/2007 301531 503394 0 Sand 5123 10229/11/2007 301542 503369 13 Sand 14708 17029/11/2007 301447 503464 10 Sand 17009 16842

29/11/2007 301456 503466 17 Sand 43832 29729/11/2007 301445 503486 12 Sand 6835 13829/11/2007 301469 503491 1 Sand 20 2870129/11/2007 301725 503567 17 Sand 33524 27630/11/2007 301683 503445 6 Sand 9725 14730/11/2007 301692 503439 7 Sand 4612 10530/11/2007 301698 503437 15 Sand 17811 15530/11/2007 301478 503439 20 Sand 4373 9230/11/2007 301629 503370 14 Sand 6025 11530/11/2007 301640 503359 2 Sand 4904 9730/11/2007 301652 503340 7 Sand 14511 15630/11/2007 301778 503350 7 Sand 5624 10303/12/2007 301721 503622 8 Sand 45522 30203/12/2007 301713 503605 3 Sand 4322 10603/12/2007 301700 503597 4 Sand 5943 8403/12/2007 301714 503569 9 Sand 7204 9103/12/2007 301705 503568 10 Sand 47125 499003/12/2007 301687 503588 9 Sand 12907 12003/12/2007 301689 503584 10 Sand 2201 18403/12/2007 301691 503571 11 Sand 20911 14803/12/2007 301594 503484 3 Sand 15 3960103/12/2007 301673 503495 15 Sand 11807 15103/12/2007 301652 503535 0 Sand 3462 8703/12/2007 301703 503509 5 Sand 28917 21604/12/2007 301671 503475 27 Sand 572273 96504/12/2007 301682 503473 15 Sand 13006 15204/12/2007 301679 503482 6 Sand 5793 11604/01/2008 301532 503841 4 Sand 17204 21404/01/2008 301586 503784 4 Sand 4261 8804/01/2008 301656 503709 5 Sand 20 5750104/01/2008 301596 503770 4 Sand 14103 15004/01/2008 301574 503792 7 Sand 10202 13504/01/2008 301555 503814 14 Sand 44412 25704/01/2008 301493 503886 7 Sand 29708 21007/01/2008 301376 504128 0 Pebbles 21402 18407/01/2008 301227 504322 3 Pebbles 9011 12007/01/2008 301064 504534 7 Pebbles 44604 25907/01/2008 301125 504453 9 Pebbles 7571 12207/01/2008 301481 503994 10 Pebbles 10702 13708/01/2008 301555 503810 10 Sand 51105 31408/01/2008 301692 503621 2 Sand 17 10900109/01/2008 301588 503764 3 Sand 20202 28310/01/2008 301692 503514 4 Sand 9691 12410/01/2008 301758 503451 10 Sand 18002 17243

10/01/2008 301694 503522 12 Sand 27603 20811/01/2008 301469 503911 5 Sand 7200 933011/01/2008 301395 504021 9 Sand 17301 17111/01/2008 301332 504110 7 Sand 17101 17011/01/2008 301368 504079 14 Sand 13000 14111/01/2008 301325 504139 5 Sand 12501 14916/01/2008 300544 504809 4 Sand 14102 15216/01/2008 300611 504913 2 Sand 21 7050122/01/2008 301270 504227 7 Sand 109010 44722/01/2008 301050 504536 5 Sand 25102 21822/01/2008 301019 504561 5 Pebbles 21302 19322/01/2008 300765 504933 5 Sand 74908 36123/01/2008 301268 504018 7 Sand 8101 14323/01/2008 301217 504295 6 Shingle 13501 16423/01/2008 301241 504285 9 Shingle 49205 38024/01/2008 300869 504557 2 Sand 128 223 1966124/01/2008 300712 505049 5 Sand 16612 16625/01/2008 300884 504596 10 Sand 23916 18925/01/2008 300945 504521 2 Sand 19 5950225/01/2008 301126 504408 10 Pebbles 111074 40429/01/2008 300415 505107 6 Sand 30713 21730/01/2008 301315 504020 5 Sand 6652 30930/01/2008 301313 504023 5 Sand 10904 12630/01/2008 301367 503906 4 Sand 9954 12130/01/2008 301290 504035 7 Sand 13405 14430/01/2008 301176 504358 5 Sand 29312 19531/01/2008 301656 503749 30 Shingle 875083 493031/01/2008 301660 503728 3 Pebbles 16906 16831/01/2008 301147 504243 18 Sand 78632 32831/01/2008 301165 504210 4 Sand 11305 14231/01/2008 301128 504266 11 Sand 33714 21931/01/2008 301123 504262 8 Sand 23310 18105/02/2008 300890 504636 18 Sand 65210 29505/02/2008 300901 504628 6 Sand 46307 25006/02/2008 301560 503834 5 Shingle 29905 21906/02/2008 301543 503454 6 Shingle 51918 30206/02/2008 301424 503806 8 Sand 32311 41007/02/2008 301633 503478 4 Sand 25102 19107/02/2008 301677 503441 12 Sand 41112 25007/02/2008 301344 504010 5 Sand 39211 24307/02/2008 301320 504032 2 Sand 26809 18107/02/2008 301290 504077 20 Sand 126 32607/02/2008 301018 504320 3 Sand 20 20000107/02/2008 301022 504295 15 Sand 48017 25044

07/02/2008 301022 504295 7 Sand 24108 17808/02/2008 301360 503812 18 Sand 31011 19708/02/2008 301335 503995 30 Sand 661186 104108/02/2008 301315 504002 5 Sand 9043 37511/02/2008 301305 504026 5 Sand 12103 13011/02/2008 301336 503982 5 Sand 13603 14611/02/2008 301319 504086 2 Sand 13904 14112/02/2008 301116 503937 2 Sand 7562 10812/02/2008 301224 504019 3 Sand 17304 15513/02/2008 301140 504140 8 Sand 183029 50413/02/2008 300988 504039 8 Sand 11604 19613/02/2008 300961 504055 7 Sand 13905 24513/02/2008 301453 503314 5 Sand 12302 97613/02/2008 301390 503540 3 Sand 9963 15913/02/2008 301377 503561 3 Sand 165057 59913/02/2008 301404 503502 8 Sand 19407 21614/02/2008 300977 503961 10 Sand 69420 38314/02/2008 300938 504007 6 Sand 22207 20714/02/2008 300914 504050 5 Sand 51417 31903/03/2008 301691 503469 5 Sand 18401 18503/03/2008 301708 503413 14 Sand 55801 35603/03/2008 301724 503407 8 Sand 42901 27303/03/2008 301726 503419 2 Sand 8210 12903/03/2008 301685 503446 4 Sand 30001 21904/03/2008 301670 503456 4 Sand 6921 13504/03/2008 301688 503451 5 Sand 17802 26406/03/2008 301656 503495 10 Sand 52605 30906/03/2008 301594 503561 17 Sand 78107 37606/03/2008 301444 503344 12 Sand 52705 32106/03/2008 301631 503598 33 Sand 457043 106807/03/2008 301635 503606 8 Sand 43902 29211/03/2008 301493 503715 12 Sand 22502 25213/03/2008 301431 503818 10 Sand 6871 12213/03/2008 301323 503522 6 Sand 35503 25213/03/2008 301315 503520 6 Sand 29603 23513/03/2008 301460 503832 25 Sand 183017 56123/06/2008 301669 503513 2 Sand 26202 22223/06/2008 301597 503183 11 Sand 44604 29723/06/2008 301532 503243 2 Sand 12101 20223/06/2008 301540 503231 5 Sand 28803 23623/06/2008 301539 503223 11 Sand 130 232 1931124/06/2008 301618 503558 4 Sand 6880 12024/06/2008 301561 503150 4 Sand 88503 42324/06/2008 301505 503252 5 Sand 15201 42545

24/06/2008 301662 503500 4 Sand 26302 24024/06/2008 301529 503674 3 Sand 18902 18524/06/2008 301664 503524 4 Sand 25 6890024/06/2008 301567 503844 3 Shingle 112011 44725/06/2008 300976 504033 10 Sand 28703 22425/06/2008 301068 504276 10 Sand 14502 15925/06/2008 301055 504314 5 Sand 63010 34025/06/2008 301226 504259 2 Shingle 11002 14426/06/2008 301355 504084 2 Sand 20606 21726/06/2008 301384 504048 14 Sand 19005 21326/06/2008 301173 504333 4 Shingle 35910 026/06/2008 301421 504016 4 Shingle 22 4270126/06/2008 301344 504117 3 Shingle 62818 47130/06/2008 301189 503794 9 Sand 26702 21930/06/2008 301203 503764 3 Sand 8471 12730/06/2008 301222 503622 4 Sand 13901 16501/07/2008 301365 503561 4 Sand 18802 18001/07/2008 301369 503507 3 Sand 13301 16201/07/2008 301341 503517 4 Sand 10201 13801/07/2008 301352 503553 4 Sand 6671 16901/07/2008 301383 503523 7 Sand 19903 20402/07/2008 301672 503715 7 Shingle 38904 25702/07/2008 301584 503816 5 Shingle 37604 25902/07/2008 301798 503539 4 Shingle 112011 44503/07/2008 301011 504558 5 Shingle 26001 21703/07/2008 301019 504553 5 Shingle 24501 20603/07/2008 301121 504421 5 Shingle 13601 15903/07/2008 301162 503884 5 Sand 4751 9703/07/2008 301126 503900 1 Sand 43610 26903/07/2008 301159 503857 5 Sand 7332 12304/07/2008 300973 504011 17 Sand 127035 47804/07/2008 301061 503892 3 Sand 7332 11704/07/2008 301024 503914 2 Sand 18005 17804/07/2008 301080 503845 10 Sand 20806 18807/07/2008 301356 503354 18 Sand 61209 39907/07/2008 301276 503596 4 Sand 31503 25207/07/2008 301408 503835 4 Sand 14201 15308/07/2008 301308 503564 5 Sand 38704 25908/07/2008 301314 503565 4 Sand 21 8700115/09/2008 300690 504947 5 Sand 21002 19417/09/2008 301608 503591 2 Sand 17 652017/09/2008 301670 503518 4 Sand 29603 20217/09/2008 301544 503679 10 Sand 11801 13417/09/2008 301684 503513 30 Sand 166025 49746

19/09/2008 301388 503561 10 Sand 8403 12319/09/2008 301347 503610 3 Sand 6852 10519/09/2008 301405 503545 10 Sand 17606 16919/09/2008 301411 503537 4 Sand 7703 11319/09/2008 301331 503634 5 Sand 21808 20919/09/2008 301367 503595 8 Sand 6843 23819/09/2008 301415 503540 4 Sand 23 13400423/09/2008 301957 503234 15 Sand 43707 34023/09/2008 302005 503186 1 Sand 26 7990123/09/2008 301623 503590 9 Sand 7932 11623/09/2008 301723 503492 14 Sand 22905 18723/09/2008 301666 503562 7 Sand 27413 19624/09/2008 302176 502947 1 Sand 9203 22725/09/2008 301251 504248 20 Sand 48814 26625/09/2008 301363 504096 20 Sand 88025 35230/09/2008 300950 504639 10 Sand 259023 73206/10/2008 301670 503545 8 Sand 15203 15208/10/2008 301728 503503 3 Sand 9422 17315/10/2008 300412 504721 5 Sand 5060 9616/10/2008 300412 504795 0 Sand 5040 8716/10/2008 301040 504496 10 Sand 32203 21017/10/2008 301185 504294 10 Sand 11500 12120/10/2008 301352 503907 20 Sand 83707 43520/10/2008 301340 503929 15 Sand 63606 39220/10/2008 301366 504075 3 Sand 23602 24720/10/2008 301322 504144 6 Sand 14202 14821/10/2008 301265 504210 4 Sand 12401 14321/10/2008 301143 504351 12 Sand 30205 24321/10/2008 301232 504244 4 Sand 14202 17021/10/2008 301222 504246 7 Sand 16903 18222/10/2008 301451 503993 10 Shingle 21602 20222/10/2008 301474 503960 4 Shingle 30405 23522/10/2008 301443 503997 10 Shingle 48708 43022/10/2008 301411 503810 12 Sand 11404 11723/10/2008 301716 503614 3 Sand 9743 10623/10/2008 302304 502852 9 Pebbles 25409 19823/10/2008 301691 503493 7 Sand 15005 18723/10/2008 301642 503562 10 Sand 48517 29224/10/2008 301704 503574 20 Sand 184052 52524/10/2008 301651 503576 20 Sand 87825 391024/10/2008 301666 503551 5 Sand 9173 61224/10/2008 301594 503591 4 Sand 22808 16927/10/2008 301977 503211 10 Sand 9321 18127/10/2008 300666 504815 6 Sand 5661 9347

27/10/2008 302058 503065 5 Sand 12802 25428/10/2008 301567 503611 12 Sand 20803 18428/10/2008 301598 503589 6 Sand 2630 6829/10/2008 301956 503246 9 Sand 27803 22230/10/2008 300457 504948 5 Sand 120 189 1710831/10/2008 301330 503496 5 Sand 8652 11331/10/2008 300424 504811 0 Sand 24 8740131/10/2008 301170 503730 4 Sand 26508 22831/10/2008 301475 503732 15 Sand 25307 46003/11/2008 301078 504333 20 Sand 70211 40420/11/2008 301696 503514 4 Sand 9881 15520/11/2008 301643 503574 17 Sand 12101 16920/11/2008 301724 503537 20 Sand 169047 60420/11/2008 301655 503587 3 Sand 29 8130220/11/2008 301705 503564 5 Sand 13505 15520/11/2008 301670 503554 11 Sand 134055 63220/11/2008 301715 503516 13 Sand 43221 27120/11/2008 301670 503569 15 Sand 72839 37320/11/2008 301930 503262 30 Sand 624454 118020/11/2008 301697 503540 5 Sand 41430 28521/11/2008 301708 503619 9 Sand 25 7140421/11/2008 301673 503570 7 Sand 42531 30021/11/2008 301932 503255 7 Sand 12210 15321/11/2008 301800 503322 10 Sand 43938 28521/11/2008 301759 503429 10 Sand 37635 21721/11/2008 301727 503473 5 Sand 8730 12424/11/2008 302137 503009 7 Sand 29629 22524/11/2008 301295 503773 3 Sand 12413 15124/11/2008 301323 503751 16 Sand 49051 29524/11/2008 301297 503793 6 Sand 7408 13024/11/2008 302277 502817 6 Sand 7971 12625/11/2008 302288 502842 7 Shingle 17023 18225/11/2008 302140 502975 4 Sand 5778 19525/11/2008 302247 502840 30 Sand/Pebbles 26 10927/11/2008 301336 504112 4 Sand 17553 30927/11/2008 301298 504157 9 Sand 12839 47828/11/2008 301440 503809 8 Sand 4212 15528/11/2008 301440 503804 4 Sand 7422 19828/11/2008 301441 503804 4 Sand 9428 24728/11/2008 301457 503770 4 Sand 6259 29201/12/2008 301280 504090 2 Sand 8133 23101/12/2008 301487 503728 20 Sand 29382 41901/12/2008 301458 503781 3 Sand 5476 13101/12/2008 301431 503868 3 Sand 4994 34548

02/12/2008 301560 503634 3 Sand 8091 72302/12/2008 301585 503614 1 Sand 20148 16702/12/2008 301277 503979 4 Sand 9493 11103/12/2008 300478 504920 6 Sand 10227 26904/12/2008 300688 504884 7 Sand 16142 33104/12/2008 301096 504436 10 Shingle 41408 48304/12/2008 301073 504468 3 Shingle 43313 50908/12/2008 300936 504505 0 Sand 4651 19308/12/2008 301201 503873 9 Sand 5383 21209/12/2008 301551 503862 9 Shingle 32742 27109/12/2008 301392 504079 12 Sand 64383 36109/12/2008 301336 504152 9 Shingle 31645 23109/12/2008 301662 503717 3 Pebbles 5828 10809/12/2008 301473 503964 8 Shingle 29141 22709/12/2008 301492 503934 0 Shingle 17527 23209/12/2008 301391 503743 6 Sand 4961 16609/12/2008 301333 503827 7 Sand 14734 30909/12/2008 301364 503778 6 Sand 19445 33509/12/2008 301038 504026 0 Sand 6044 23609/12/2008 301414 503694 17 Sand 25840 21509/12/2008 301065 504069 3 Sand 4807 11009/12/2008 301123 503997 0 Sand 22 5140710/12/2008 301602 503784 3 Shingle 13520 21410/12/2008 301627 503749 2 Shingle 5240 8910/12/2008 301426 504013 0 Sand 25 6670910/12/2008 301284 504198 8 Sand 21850 40710/12/2008 301555 503838 4 Shingle 22042 25410/12/2008 301470 503943 4 Shingle 74271 69210/12/2008 301235 504259 5 Sand 119275 010/12/2008 301585 503795 6 Shingle 29116 23110/12/2008 301523 503875 5 Shingle 13306 16110/12/2008 301234 504249 5 Sand 37286 50410/12/2008 301166 503965 5 Sand 7708 25210/12/2008 301398 503689 23 Sand 76137 31610/12/2008 301208 503908 11 Sand 23042 19110/12/2008 301357 503745 4 Sand 12307 77610/12/2008 301138 504005 3 Sand 25759 42610/12/2008 301328 503786 4 Sand 11527 28510/12/2008 301112 504046 3 Sand 8720 25211/12/2008 301166 504345 3 Sand 42395 53011/12/2008 301204 504300 2 Sand 8960 24712/12/2008 300396 505098 9 Sand 5973 20712/12/2008 300311 505240 0 Sand 30 4390812/12/2008 301270 504236 5 Shingle 15535 28849

16/01/2009 301522 503320 7 Sand 36708 45616/01/2009 301487 503413 6 Sand 4201 16519/01/2009 301627 503665 5 Sand 13813 31119/01/2009 301633 503658 2 Sand 5942 19719/01/2009 301645 503646 6 Sand 16115 35219/01/2009 301637 503653 12 Sand 31529 75020/01/2009 301268 504121 13 Sand 22219 35420/01/2009 301178 504067 2 Sand 26 16501120/01/2009 301199 504032 4 Sand 28 11700820/01/2009 301901 503302 10 Sand 54647 56120/01/2009 302023 503170 6 Shingle 31127 42821/01/2009 301681 503589 10 Sand 51708 83021/01/2009 301588 503693 5 Sand 6886 23421/01/2009 301610 503662 10 Sand 39306 42121/01/2009 301637 503619 11 Sand 26404 36921/01/2009 301655 503595 0 Sand 36 10200621/01/2009 301685 503529 0 Sand 25704 34729/01/2009 301672 503513 3 Sand 4181 19130/01/2009 301670 503528 11 Sand 11503 205003/02/2009 300904 504598 1 Sand 44 7720006/02/2009 301572 503689 11 Sand 10807 27806/02/2009 301566 503694 18 Sand 21013 39006/02/2009 301539 503719 2 Sand 10807 28106/02/2009 301564 503684 12 Sand 59337 58006/02/2009 301502 503834 7 Sand 55835 57106/02/2009 301480 503826 6 Sand 14109 30006/02/2009 301463 503895 2 Sand 45 597009/02/2009 300599 505204 4 Sand 14807 35909/02/2009 300549 505258 13 Sand 58737 35010/02/2009 300637 504963 5 Sand 20509 41611/02/2009 300694 504947 1 Sand 55 5380112/02/2009 300580 504847 2 Sand 7933 25912/02/2009 300666 504977 0 Sand 25 9890217/02/2009 300745 504780 7 Sand 7304 27818/02/2009 300465 505144 6 Sand 11805 30718/02/2009 300470 505139 0 Sand 11234 25219/02/2009 300257 505418 7 Sand 10904 34727/04/2009 300581 504607 9 Sand 6031 22728/04/2009 301083 504518 12 Pebbles 69908 76128/04/2009 301097 504496 10 Pebbles 7961 28528/04/2009 301655 503766 15 Pebbles 175019 126029/04/2009 300109 505388 6 Sand 80 125 620929/04/2009 300311 505400 1 Sand 25 7130230/04/2009 300036 505455 10 Sand 3350 15050

30/04/2009 300033 505424 5 Sand 9701 24326/05/2009 301263 504266 6 Pebbles 18601 33026/05/2009 301379 504111 6 Pebbles 24902 39726/05/2009 301471 503988 8 Pebbles 30402 42128/05/2009 301097 504128 12 Sand 37103 47628/05/2009 301181 504058 15 Sand 47418 57828/05/2009 301195 504063 2 Sand 9424 27329/05/2009 302037 503135 10 Sand 10103 26229/05/2009 302141 503004 9 Sand 10303 51629/05/2009 302106 503062 3 Sand 6542 21529/05/2009 301944 503261 1 Sand 7582 23617/06/2009 301649 503553 10 Sand 26401 43318/06/2009 301910 503287 9 Sand 22801 40918/06/2009 301488 503512 10 Sand 24501 51418/06/2009 301511 503385 3 Sand 6870 760018/06/2009 301463 503464 14 Sand 104006 84418/06/2009 301472 503502 9 Sand 11401 29218/06/2009 301531 503689 3 Sand 122 206 1626319/06/2009 301604 503665 4 Sand 6194 23122/06/2009 301561 503242 5 Sand 4243 18922/06/2009 301600 503637 10 Sand 15211 33823/06/2009 301524 503911 5 Pebbles 14408 023/06/2009 301847 503484 6 Pebbles 19411 38520/07/2009 301715 503568 20 Sand 80209 78020/07/2009 301695 503240 3 Sand 32704 49720/07/2009 301658 503260 5 Sand 9131 25221/07/2009 300937 504595 1 Sand 18803 021/07/2009 301165 504041 4 Sand 15003 31921/07/2009 301235 504005 2 Sand 84 132 716723/07/2009 301183 503709 18 Sand 62416 70123/07/2009 301404 503412 7 Sand 40210 52823/07/2009 301458 503323 10 Sand 57615 105023/07/2009 301361 503331 10 Sand 18605 34023/07/2009 301087 503497 8 Sand 42811 108023/07/2009 301421 503399 9 Sand 15404 45123/07/2009 301438 503383 8 Sand 13303 32323/07/2009 301478 503332 8 Sand 4671 31723/07/2009 301448 503373 4 Sand 9252 25923/07/2009 301670 503593 3 Sand 10603 25724/07/2009 301679 502915 2 Sand 11302 28324/07/2009 301618 502907 0 Sand 28806 43024/07/2009 301792 502858 3 Sand 30 1640119/08/2009 300462 505151 3 Sand 17901 115020/08/2009 300503 504860 4 Sand 12500 30251

22/09/2009 301787 503592 7 Pebbles 19408 37322/09/2009 300177 505627 0 Sand 30 1130022/09/2009 300250 505506 4 Sand 26 5130123/09/2009 300525 504824 2 Sand 28 3600123/09/2009 300664 504860 3 Sand 30 3750123/09/2009 300704 504911 2 Sand 28 1990124/09/2009 300666 504851 2 Sand 27 1380024/09/2009 300608 504933 2 Sand 31 3010124/09/2009 300527 504849 3 Sand 7132 21824/09/2009 300528 504880 2 Sand 28 1790124/09/2009 300574 504863 1 Sand 24 5870224/09/2009 300660 504877 3 Sand 24 2000124/09/2009 300726 504872 8 Sand 28 1250124/09/2009 300775 504874 9 Sand 22306 37625/09/2009 301664 503531 4 Sand 27 1140125/09/2009 301749 503434 1 Sand 35 1160126/09/2009 302094 503151 3 Pebbles 20916 39726/09/2009 301659 503770 3 Pebbles 41231 62529/09/2009 300299 505468 5 Sand 27 4180229/09/2009 300317 505431 3 Sand 11907 30429/09/2009 300202 505364 5 Sand 27 3120229/09/2009 300282 505361 5 Sand 35 4720227/10/2009 300846 504499 2 Sand 27 9720327/10/2009 300834 504566 2 Sand 33 2950127/10/2009 300823 504599 1 Sand 27 2820127/10/2009 300890 504684 1 Sand 20 1230027/10/2009 300932 504609 3 Sand 29 1320128/10/2009 300557 505128 2 Sand 29 2300128/10/2009 300566 505094 6 Sand 30 9860428/10/2009 300549 505107 2 Sand 34 984028/10/2009 300530 505103 3 Sand 34 2400128/10/2009 300519 505108 3 Sand 30 3140128/10/2009 300500 505131 5 Sand 30 2600128/10/2009 300483 505127 2 Sand 25 1000128/10/2009 300453 505153 3 Sand 20 2320228/10/2009 300485 505176 2 Sand 29 2560228/10/2009 300489 505178 3 Sand 29 1540129/10/2009 301627 503628 12 Sand 45237 91329/10/2009 301640 503328 7 Sand 308251 107729/10/2009 301620 503352 9 Sand 18523 32829/10/2009 301647 503338 11 Sand 10514 28529/10/2009 301619 503604 10 Sand 10814 27630/11/2009 300700 504860 2 Sand 21 4050404/02/2010 301906 503296 3 Sand 83501 69752

08/02/2010 301171 504108 3 Sand 25 3810008/02/2010 300548 504910 2 Sand 29 3540008/02/2010 300529 505164 4 Sand 33 2050008/02/2010 300514 505175 2 Sand 22 2070008/02/2010 300528 505129 2 Sand 26 769009/02/2010 300635 504957 2 Sand 22 1230009/02/2010 300669 504891 2 Sand 21 3200009/02/2010 300539 504845 3 Sand 29 3560109/02/2010 300514 504862 3 Sand 29 2270110/02/2010 300690 504867 3 Sand 28 2260110/02/2010 300596 504872 3 Sand 28 2040110/02/2010 300539 504809 3 Sand 29 2900110/02/2010 300544 504798 2 Sand 28 2580110/02/2010 300640 504852 1 Sand 29 12400011/02/2010 300744 504862 2 Sand 31 2310111/02/2010 300447 504841 1 Sand 31 3560211/03/2010 301595 503680 2 Sand 32937 53711/03/2010 301592 503678 5 Sand 22626 40411/03/2010 301667 503531 2 Sand 26 5280811/03/2010 301448 503562 6 Sand 14216 33311/03/2010 301399 503542 5 Sand 31135 46112/03/2010 301600 503677 4 Sand 27 25203812/03/2010 301583 503701 4 Sand 29 3380512/03/2010 301598 503690 4 Sand 26 2410412/03/2010 301592 503701 2 Sand 22 4170712/03/2010 301646 503637 17 Sand 15116 35212/03/2010 301432 503565 2 Sand 25 2070412/03/2010 301362 503500 2 Sand 41244 54012/03/2010 301344 503523 3 Sand 17118 54012/03/2010 301349 503515 3 Sand 26 244012/03/2010 301355 503505 2 Sand 16417 36615/03/2010 301615 503708 1 Sand 24 3350615/03/2010 301353 503503 5 Sand 37233 015/03/2010 301465 503832 3 Sand 31 4110715/03/2010 301480 503813 2 Sand 32 4980815/03/2010 301356 503499 2 Sand 40836 53715/03/2010 301400 503431 13 Sand 20618 42316/03/2010 301521 503776 10 Sand 13212 31416/03/2010 301545 503746 11 Sand 50244 60616/03/2010 301485 503539 4 Sand 24 2910516/03/2010 301351 503491 3 Sand 21 2610416/03/2010 301345 503498 3 Sand 7166 77216/03/2010 301350 503492 4 Sand 9929 64517/03/2010 301427 503538 2 Sand 24 2950553

17/03/2010 301446 503542 2 Sand 26 1820417/03/2010 301432 503559 2 Sand 25 12802717/03/2010 301553 503757 5 Sand 6656 19817/03/2010 301537 503781 3 Sand 6035 20817/03/2010 301534 503797 2 Sand 27 1500317/03/2010 301516 503821 15 Sand 15649 53017/03/2010 301554 503774 0 Sand 28 2170518/03/2010 301234 503701 12 Sand 24818 018/03/2010 301381 504036 1 Sand 28 3590818/03/2010 301369 504076 0 Sand 23 3550818/03/2010 301285 504140 2 Sand 25820 101019/03/2010 301209 503742 3 Sand 26 2020419/03/2010 301077 504258 0 Sand 24 4150904/05/2010 300574 504768 2 Sand 22319 36104/05/2010 300505 504756 3 Sand 25 4450304/05/2010 300492 504790 2 Sand 32 1640104/05/2010 300574 504808 1 Sand 31 2190104/05/2010 300606 504783 1 Sand 29 5160304/05/2010 300602 504876 8 Sand 27 11100705/05/2010 300281 505593 2 Sand 28 3500205/05/2010 300205 505520 1 Sand 32 2110105/05/2010 300116 505514 2 Sand 28 5850405/05/2010 300188 505554 4 Sand 29 1520105/05/2010 300276 505450 1 Sand 29 1760105/05/2010 300309 505435 1 Sand 30 3050205/05/2010 300315 505431 2 Sand 34 1230105/05/2010 300287 505469 2 Sand 28 1350105/05/2010 300226 505676 1 Sand 24 621106/05/2010 300381 505405 7 Sand 19624 17906/05/2010 300385 505257 1 Sand 29 2070206/05/2010 301732 503415 4 Sand 37145 25206/05/2010 301725 503424 2 Sand 25 6110506/05/2010 301654 503204 2 Sand 25 4640406/05/2010 301710 503473 1 Sand 25 1820206/05/2010 301670 503491 18 Sand 74293 30406/05/2010 301636 503587 1 Sand 23 3940307/05/2010 301784 503541 2 Sand 26 4140407/05/2010 301811 503492 0 Sand 21426 27301/06/2010 301399 503475 13 Sand 40634 26401/06/2010 301370 503419 5 Sand 14009 32301/06/2010 301400 503482 9 Sand 6164 22301/06/2010 301358 503535 1 Sand 21 6090401/06/2010 301340 503565 2 Sand 21 5210301/06/2010 301356 503587 13 Sand 34833 25054

02/06/2010 301552 503644 1 Sand 30 1970102/06/2010 301519 503685 2 Sand 24 6740402/06/2010 301510 503716 8 Sand 16109 32802/06/2010 301666 503637 2 Sand 4573 20102/06/2010 301641 503668 2 Sand 10406 55202/06/2010 301550 503784 1 Sand 29 4440302/06/2010 301664 503643 1 Sand 7414 23303/06/2010 301568 503765 2 Sand 27 7730503/06/2010 301577 503753 3 Sand 4762 21603/06/2010 301640 503682 2 Sand 29 3340203/06/2010 301589 503741 2 Sand 9005 28103/06/2010 301612 503714 20 Sand 73839 76803/06/2010 301493 503551 1 Sand 31 3880303/06/2010 301377 503541 2 Sand 30 3570203/06/2010 301447 503554 1 Sand 27 2840203/06/2010 301650 503677 3 Sand 8885 26903/06/2010 301591 503744 1 Sand 24 2750204/06/2010 301493 503818 1 Sand 28 3110204/06/2010 301489 503831 4 Sand 29 1290104/06/2010 301303 503741 2 Sand 8254 24704/06/2010 301309 503644 3 Sand 17308 34504/06/2010 301227 503746 2 Sand 29 5120428/06/2010 302162 502949 2 Sand 6901 22129/06/2010 301963 502982 9 Shingle 55 61800129/06/2010 302002 503023 2 Shingle 25 4270001/07/2010 302116 502806 25 Sand/Shingle 37 9102/07/2010 301677 503255 0 Pebbles 27 3890102/07/2010 302256 502874 1 Sand 23 2390002/08/2010 300595 504934 0 Sand 23 2670002/08/2010 300618 504940 1 Sand 29 2680002/08/2010 300664 504975 1 Sand 25 2480003/08/2010 300756 504932 1 Sand 29 3630003/08/2010 300740 504854 0 Sand 29 2910003/08/2010 300478 505167 1 Sand 20 964003/08/2010 300407 505114 2 Sand 19 3850103/08/2010 300392 505040 0 Sand 29 1400003/08/2010 300423 505034 1 Sand 28 8260203/08/2010 300476 505147 2 Sand 24 3530103/08/2010 300528 505134 1 Sand 22 1450004/08/2010 300637 504966 0 Sand 19 6120204/08/2010 300726 504894 0 Sand 34 4730204/08/2010 300717 504908 0 Sand 25 1500105/08/2010 300446 505047 1 Sand 26 1390005/08/2010 300593 505127 0 Sand 21 1230055

31/08/2010 300219 505597 0 Sand 33 1190031/08/2010 301176 504175 1 Sand 41 3430001/09/2010 301005 504353 1 Sand 31 3250001/09/2010 301031 504347 0 Sand 32 1460001/09/2010 301453 503947 4 Sand 10501 28501/09/2010 301423 503992 30 Sand 174022 117201/09/2010 301376 504057 7 Sand 17906 35202/09/2010 301382 503975 0 Sand 33 1070002/09/2010 301196 504160 10 Sand 30208 47802/09/2010 301210 504148 3 Sand 39 3540102/09/2010 301203 503944 4 Sand 36 4600102/09/2010 301122 504406 2 Shingle 12003 29702/09/2010 300967 504426 3 Sand 35 2350103/09/2010 300917 504751 23 Pebbles 803360 237503/09/2010 301363 504142 2 Pebbles 16007 117003/09/2010 301641 503772 8 Pebbles 59226 68503/09/2010 302103 503124 2 Pebbles 11305 32303/09/2010 301313 503696 3 Sand 36 9320203/09/2010 301292 503742 11 Sand 59226 63703/09/2010 301380 504056 2 Sand 30 2090103/09/2010 301451 503954 1 Sand 34 2100127/09/2010 300514 504853 Sand 3910 15727/09/2010 300470 504872 Sand 27 976027/09/2010 300666 504989 0 Sand 30 1140027/09/2010 300752 504794 7 Sand 34 5170027/09/2010 300752 504784 1 Sand 36 1040027/09/2010 300778 504842 1 Sand 29 1340028/09/2010 300736 504742 1 Sand 34 4130128/09/2010 300670 504562 3 Sand 27 4160128/09/2010 300746 504605 Sand 30 4310129/09/2010 300949 504651 2 Sand 30 5080129/09/2010 300976 504611 19 Sand 92436 81829/09/2010 300911 504547 1 Sand 32 1980129/09/2010 300911 504540 3 Sand 28 692029/09/2010 300957 504486 2 Sand 36 1140029/09/2010 300934 504461 0 Sand 27 6110229/09/2010 300937 504485 0 Sand 33 997030/09/2010 300408 505422 0 Sand 36 220030/09/2010 300412 505414 2 Sand 32 3660230/09/2010 300320 505539 2 Sand 30 1650130/09/2010 300369 505473 0 Sand 35 691030/09/2010 300167 505326 0 Sand 30 1210101/10/2010 301415 504032 3 Sand 34 3840326/10/2010 301765 503438 1 Sand 29 1520056

26/10/2010 301780 503422 24 Sand 67004 35727/10/2010 301679 503234 4 Sand 34 2910027/10/2010 301594 503583 3 Sand 34 5020027/10/2010 301569 503604 2 Sand 6542 22027/10/2010 301702 503640 0 Sand 36 2030028/10/2010 301608 503371 1 Sand 30 6280128/10/2010 301635 503567 1 Sand 29 1650028/10/2010 301674 503537 1 Sand 33 4150128/10/2010 301814 503469 4 Sand 30 1630001/11/2010 301953 503238 2 Sand 34 1710001/11/2010 301613 503634 9 Sand 5751 22101/11/2010 301536 503642 0 Sand 30 1750001/11/2010 301568 503804 12 Shingle 14403 338Table A.3: Location and activities for particles recovered at Sellafield57

Position (BNG)Activity of recovered particle (Bq)Date x y d (cm) Substrate137 Cs241 Am60 Co29/01/2007 299910 505941 1 Sand 1040130/01/2007 300063 505941 1 Shingle 1950102/11/2007 299640 506422 3 Sand 5720 11405/11/2007 299762 506152 0 Sand 15801 817/06/2008 299314 506557 4 Sand 18601 18818/06/2008 300086 505496 6 Sand 35003 113019/09/2008 300008 505668 6 Sand 11503 14919/09/2008 300047 505867 8 Sand 6432 11313/07/2009 300198 505698 2 Sand 6591 22213/07/2009 300013 505795 4 Sand 7181 23017/07/2009 300064 505811 3 Sand 25 12800207/08/2009 299668 505983 1 Sand 27 3760104/11/2009 300109 505727 2 Sand 25 3240204/11/2009 300104 505729 3 Sand 28 1520104/11/2009 300117 505699 1 Sand 27 771105/11/2009 300146 505705 1 Sand 24 5030305/11/2009 300110 505759 5 Sand 10509 27106/11/2009 300154 505722 3 Sand 29 1880106/11/2009 300150 505730 0 Sand 25 2090206/11/2009 300145 505740 2 Sand 9214 18606/11/2009 300140 505757 2 Sand 30 623109/11/2009 299939 505932 2 Sand 27 623009/11/2009 299942 505927 2 Sand 27 1970209/11/2009 299965 505927 2 Sand 25 2150409/11/2009 299979 505915 2 Sand 23 1450109/11/2009 300085 505854 5 Sand 28 661110/11/2009 299525 506425 7 Sand 27 7970010/11/2009 299563 506481 3 Sand 26 3450611/11/2009 299497 506550 4 Sand 21 3750611/11/2009 299463 506521 4 Sand 28 1540211/11/2009 299470 506499 5 Sand 25 867112/11/2009 300096 505865 1 Sand 22 1050112/11/2009 300117 505837 0 Sand 25 1840212/11/2009 299490 506578 3 Sand 29 2590313/11/2009 300088 505872 1 Sand 45 1450213/11/2009 300116 505835 2 Sand 33 2960313/11/2009 300015 505736 1 Sand 32 3060318/11/2009 300033 505842 2 Sand 29 3600319/11/2009 300058 505882 2 Sand 31 5710415/02/2010 299975 505921 3 Sand 27 5820315/02/2010 299972 505951 0 Sand 27 3180216/02/2010 299996 505857 3 Sand 29 6590258

17/02/2010 299936 505683 3 Sand 29 1450117/02/2010 299911 505666 4 Sand 7908 20417/02/2010 300097 505760 3 Sand 8679 21719/02/2010 299372 506434 2 Sand 25 3150201/03/2010 300136 505734 0.5 Sand 31 1800001/03/2010 300108 505775 3 Sand 34 13800203/03/2010 300181 505685 4 Sand 25 2280004/03/2010 299951 505752 2 Sand 25 4070104/03/2010 299936 505531 1 Sand 22 748004/03/2010 299934 505815 3 Sand 24 3320105/03/2010 299886 505775 2.5 Sand 30 1170006/03/2010 299932 506003 2 Sand 26 2630206/03/2010 299932 506006 1 Sand 32 2030206/03/2010 299770 505862 1 Sand 26 2960306/03/2010 300002 505702 1 Sand 26 1900206/03/2010 300019 505698 1 Sand 29 2050207/03/2010 300059 505914 4 Sand 29 2080207/03/2010 300130 505798 0.5 Sand 23 1350107/03/2010 299622 506200 3 Sand 12304 13807/03/2010 299670 506123 1 Sand 25 5340607/03/2010 299565 506417 3 Sand 26 2120307/03/2010 299595 506392 4 Sand 28 1640207/03/2010 300107 505814 1 Sand 31 2580407/03/2010 300057 505877 2 Sand 27 3090408/03/2010 299505 506504 3 Sand 21 1250008/03/2010 299501 506483 4 Sand 29 1460108/03/2010 299509 506550 5 Sand 34 2640108/03/2010 299504 506582 6 Sand 84 159 892209/03/2010 299714 506341 2 Sand 25 1550109/03/2010 299612 506420 0 Sand 24 4140209/03/2010 299437 506534 2 Sand 28 12600809/03/2010 299445 506528 1 Sand 24 1440209/03/2010 299604 506462 3 Sand 8782 33810/03/2010 299565 506505 3 Sand 22 3110519/05/2010 300143 505738 3 Sand 33 1750119/05/2010 300139 505718 10 Sand 25 2460119/05/2010 300062 505603 2 Sand 30 1890119/05/2010 299984 505692 1 Sand 24 1110119/05/2010 300034 505612 2 Sand 26 2470119/05/2010 300196 505695 4 Sand 23 3930219/05/2010 300142 505767 4 Sand 28 2830221/05/2010 300049 505839 7 Sand 26 7200424/05/2010 300184 505717 3 Sand 20 3970224/05/2010 300024 505886 3 Sand 22 2880159

24/05/2010 299805 505799 3 Sand 30 2160124/05/2010 299746 505865 3 Sand 25 3000124/05/2010 299985 505780 5 Sand 8761 12825/05/2010 299935 506036 1 Sand 28 5080225/05/2010 299964 505992 1 Sand 30 1360125/05/2010 299926 506019 1 Sand 24 3800225/05/2010 299994 505935 3 Sand 15715 17325/05/2010 299933 505989 3 Sand 22 4150325/05/2010 299954 505963 1 Sand 24 489026/05/2010 299678 506078 2 Sand 15115 70926/05/2010 299713 506067 2 Sand 25 1020126/05/2010 299641 506201 1 Sand 27 996127/05/2010 299738 506019 10 Sand 21721 39527/05/2010 299710 506091 1 Sand 26 1850128/05/2010 299728 506132 2 Sand 29 1170009/06/2010 299547 506458 2 Sand 30 1470109/06/2010 299618 506130 1 Sand 24 2760209/06/2010 299603 506143 4 Sand 31 9150610/06/2010 299626 506387 1 Sand 27 1300110/06/2010 299644 506039 2 Sand 25 2900211/06/2010 299660 506401 1 Sand 25 2070115/06/2010 299456 506502 1 Sand 28 1410109/08/2010 299431 506596 2 Sand 48 3560110/08/2010 299666 506093 2 Sand 51 4130110/08/2010 299610 506412 0 Sand 49 658011/08/2010 299572 506192 1 Sand 52 1170011/08/2010 299552 506257 1 Sand 46 1060012/08/2010 299438 506310 1 Sand 60 4650113/08/2010 299441 506336 3 Sand 31913 21316/08/2010 299462 506352 1 Sand 59 429016/08/2010 299462 506437 1 Sand 50 861017/08/2010 299684 506148 1 Sand 57 1940018/08/2010 299744 506255 1 Sand 62 1580018/08/2010 299742 506091 1 Sand 55 1040018/08/2010 299740 506097 1 Sand 60 1910018/08/2010 299718 506149 1 Sand 58 2260118/08/2010 299757 506110 1 Sand 32 1860018/08/2010 299705 506188 4 Sand 37 1520020/08/2010 299632 506414 7 Sand 31 4270123/08/2010 299980 505987 1 Sand 32 1150026/08/2010 300023 505654 3 Sand 35 5950026/08/2010 299989 505656 1 Sand 36 7980026/08/2010 299948 505713 2 Sand 34 5730126/08/2010 300051 505811 4 Sand 13404 17060

26/08/2010 300092 505800 10 Sand 36 15800326/08/2010 300058 505844 0 Sand 36 2300102/11/2010 299905 506083 0 Sand 29 1760002/11/2010 299940 505987 0 Sand 28 17700202/11/2010 299904 506084 1 Sand 29 826002/11/2010 299935 506031 1 Sand 31 1570002/11/2010 299906 506043 1 Sand 29 1690102/11/2010 299977 505952 1 Sand 29 1170002/11/2010 299962 505982 3 Sand 31 3360102/11/2010 299941 506014 0 Sand 26 799003/11/2010 300083 505873 4 Sand 33 2260103/11/2010 300016 505889 2 Sand 33 765003/11/2010 300016 505889 2 Sand 29 3840203/11/2010 299930 505715 0 Sand 30 998103/11/2010 299986 505752 4 Sand 30 5840303/11/2010 300017 505724 2 Sand 34 891103/11/2010 300070 505885 1 Sand 29 2760203/11/2010 300098 505779 2 Sand 30 1330104/11/2010 299812 506111 4 Sand 31 2010104/11/2010 299808 506121 0 Sand 36 1690104/11/2010 299806 506117 0 Sand 33 670004/11/2010 299738 506003 1 Sand 31 1240104/11/2010 299756 505994 2 Sand 26 2250104/11/2010 299718 506060 2 Sand 34 748009/11/2010 300030 505712 0 Sand 32 1330109/11/2010 300071 505835 1 Sand 27 954110/11/2010 300100 505796 1 Sand 34 1920110/11/2010 300126 505756 2 Sand 38 12101Table A.4: Location and activities for particles recovered at Braystones61

Position (BNG)Activity of recovered particle (Bq)Date x y d (cm) Substrate137 Cs241 Am60 Co22/05/2007 296677 510804 2.5 sand 18 4300017/09/2007 296037 511597 3 sand 6791 11724/09/2007 296028 511675 1 sand 19 426028/09/2007 296279 511370 0 sand 7190 9901/10/2007 295982 511524 3 sand 4100 7801/10/2007 295898 511599 0 sand 3700 8401/04/2008 296488 511133 6 sand 61 1720011/04/2008 295874 511615 1 sand 5850 10916/04/2008 295953 511661 5 sand 19202 15002/04/2009 295928 511590 4 Sand 19401 22002/04/2009 295952 511562 3 Sand 27 7270002/07/2009 295962 511544 7 Sand 77 14307/07/2009 296078 511318 10 Sand 9411 27101/04/2010 296067 511314 1 Sand 25 2960501/04/2010 296022 511368 2 Sand 33 2560507/04/2010 296202 511384 1 Sand 25 1810207/04/2010 296201 511336 1 Sand 23 2550308/04/2010 296080 511660 2 Sand 30 2940408/04/2010 296083 511640 1 Sand 22 2100308/04/2010 296225 511252 1 Sand 24 3690608/04/2010 296197 511324 0 Sand 6727 20908/04/2010 296177 511315 2 Sand 30 5240808/04/2010 296230 511242 1 Sand 25 1580209/04/2010 296103 511612 3 Sand 22 5500816/04/2010 296129 511539 2 Sand 25 3510416/04/2010 296165 511495 2 Sand 27 2290316/04/2010 296154 511551 3 Sand 23 1260119/04/2010 296607 510826 2 Sand 30 1530220/04/2010 296631 510845 6 Sand 28 4480520/04/2010 296700 510805 2 Sand 30 3160320/04/2010 296679 510835 0 Sand 29 1010121/04/2010 296329 511202 1 Sand 22 2400221/04/2010 296272 511221 1 Sand 26 2360221/04/2010 296310 511300 1 Sand 21 1690221/04/2010 296283 511342 1 Sand 25 2140222/04/2010 296331 511411 2 Sand 28 3220322/04/2010 296154 511370 2 Sand 31 1970222/04/2010 296110 511395 2 Sand 27 1940222/04/2010 296302 511346 1 Sand 23 623122/04/2010 296203 511519 3 Sand 27 2130206/09/2010 296406 511315 3 Sand 37 5140208/09/2010 296193 511294 0 Sand 31 2520162

14/09/2010 295936 511764 2 Sand 36 1930014/09/2010 295937 511633 0 Sand 31 2220014/09/2010 295933 511795 0 Sand 30 598020/09/2010 296218 511356 0 Sand 36 1750020/09/2010 296273 511379 1 Sand 34 1120021/09/2010 296073 511482 1 Sand 34 615022/09/2010 296078 511416 2 Sand 38 2780122/09/2010 296151 511477 1 Sand 36 4840222/09/2010 296313 511376 1 Sand 30 1470115/11/2010 296145 511488 3 Sand 17103 41415/11/2010 296109 511615 1 Sand 34 503016/11/2010 296082 511546 1 Sand 33 3640116/11/2010 296038 511550 1 Sand 34 922016/11/2010 295988 511571 4 Sand 28 1640116/11/2010 295976 511648 2 Sand 25 2110117/11/2010 296212 511487 2 Sand 29 1440017/11/2010 296192 511422 2 Sand 33 1980117/11/2010 295937 511714 2 Sand 32 19401Table A.5: Location and activities for particles recovered at St Bees63

Activity of recoveredPosition (BNG)particle (Bq)Date x y d (cm) Substrate137 Cs241 Am Location03/10/2008 298689 529957 2 sand 18201 170 Workington06/11/2008 307684 542432 3 sand 7140 128 Allonby23/09/2010 297194 518862 1 Sand 30 24100 Whitehaven24/09/2010 297161 518865 2 Sand 29 14100 Whitehaven13/10/2010 296880 518400 19 Sand 292023 1362 Whitehaven05/11/2010 297057 518681 2 Sand 29 9061 Whitehaven05/11/2010 297098 518758 2 Sand 28 25102 Whitehaven05/11/2010 297095 518758 2 Sand 34 27202 WhitehavenTable A.6: Location and activities for particles recovered north of St Bees64

SSEM/2011/4730 June 2011Appendix 5Information sent to EA in support of a 150 ha beachmonitoring programme© Nuclear Decommissioning Authority 2011.

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Page 1 of 311 February 2011Stuart Page Direct tel: 019467 76597Environment AgencyGhyll MountGillan WayPenrith 40 Business ParkPenrithCA11 9BPDirect fax:Your ref:Our ref: EA/06/7733/21Dear Mr PageProposed Beach Monitoring Programme for 2011/12I attach a copy of Sellafield Ltd’s proposed beach monitoring programme for 2011/12. As inprevious years this programme is set to run from the start of April to the end of March,consistent with the financial year. Sellafield Ltd is seeking to agree this programme with theEnvironment Agency by the end of February, to ensure continuity in beach monitoringoperations at the start of April and to provide the opportunity for it to be shared with otherstakeholders (including Parish Councils) during March.At the multi-agency workshop hosted by the Environment Agency in November 2010, SellafieldLtd presented on progress against the current 250 ha programme and on findings from thebeach monitoring work done to date. The Health Protection Agency also presented on thework they are doing on the assessment of risks (with the Food Standards Agency), where theyrecommended: “Continued regular monitoring of Sellafield beach and monitoring at one or twoother beaches with high public occupancy, to provide continued reassurance that risks remainvery low”. Consistent with this recommendation, and as part of the presentation discussing theway forward for the particles in the environment work programme, Sellafield Ltd introduced theproposal for the 2011/12 beach monitoring programme, with a total target area of 150ha overthe 12 month period. The basis for a 150ha programme was briefly outlined at the workshoptogether with indicative target coverage for each of the main beach areas.The programme attached to this letter is a development from that presented in November2010; and takes into consideration points raised at the workshop. The following provides moredetail on how the programme has been developed.As a starting point, the programme incorporates regular repeat visits to Sellafield beach. Thissatisfies both the requirement for “Monthly monitoring at least 10 times per year” specified inthe Compilation of Environment Agency Requirements (CEAR) under 1/9/007; and alsoachieves regular repeat visits to Sellafield beach where the highest find-rates are observed.These regular repeat visits facilitate the ongoing removal of finds from this area of beach andA company owned by Nuclear Management Partners LtdRegistered Office: Booths Park,Chelford Road, Knutsford, Cheshire WA16 8QZCompany Registration No. 1002607

Page 2 of 3provides useful information on find numbers over time and possible rates of repopulation.The requirement for strandline monitoring has also been incorporated into the programme atappropriate quarterly intervals. This monitoring, which is less time consuming than large areabeach monitoring, has been identified alongside the need for regular vehicle maintenance.Braystones beach, with its relatively high find-rates and greater public occupancy levels thanSellafield, will continue to dominate as the beach with the largest target monitoring area. As inprevious years, monitoring will be done a number of times, in large period blocks during theprogramme year.A key feature of the 2011/12 programme is the introduction of larger blocks of Buffer Time. Inprevious programmes, week-long blocks have been incorporated to allow for recovery of theprogramme in the event that unforeseen circumstances (eg inclement weather or technicalcomplications) impact on the ability of the contractor to achieve beach target areas in anygiven monitoring block. This year, in response to concerns raised by local stakeholders aboutpossible detrimental aspects of beach monitoring operations during peak tourist seasons,Sellafield Ltd are proposing to introduce extended Buffer Time blocks around the Easter andSummer school holidays. This will mean that routine monitoring will not be scheduled to takeplace during these times, (allowing time for major vehicle maintenance etc. to be carried out ifrequired), unless extenuating circumstances require it. Where monitoring is required duringthe buffer time, all efforts will be made to avoid those beaches with the highest publicoccupancy.Recognising the introduction of two extended buffer periods, those beach areas with thehighest public occupancy rates are scheduled to be monitored as close as possible to the startand finish of these periods. For example, St Bees beach will be monitored twice between theEaster and Summer buffer periods and again soon after the Summer buffer weeks. Thisshould mean that monitoring takes place at times that are most representative of periods whenthe beaches have their highest occupancy, but without the adverse impacts of monitoringwhen large numbers of the public are present.As a result of introducing these repeat visits either side of the buffer periods; and by breakingthe majority of monitoring periods down into week-long blocks at each beach, the number ofmonitoring visits to St Bees and Seascale will be increased as part of the 2011/12 programme.As with the Sellafield beach re-visits, these repeat surveys will help inform understanding offind numbers and possible re-population rates.As part of the 2010/11 programme two periods of Investigative monitoring were introduced,providing the opportunity to return to some of the less-visited beaches and to monitor newbeach areas, utilising both vehicle and hand-held equipment (for those areas inaccessible tothe vehicle). For 2011/12 we are including beach areas from last years’ investigations asnamed beach areas in the programme (Allonby, Whitehaven North and Harrington); togetherwith a non-beach specified Investigation period. The specific inclusion of Allonby, WhitehavenNorth and Harrington, recognises the interest in continued monitoring on beach areas to thenorth of St Bees where a small number of finds have been recovered on some of the previousvisits. A decision on how best to allocate the Investigation period will be made closer to thetime; and will be based on findings from the monitoring carried out up to that point in theA company owned by Nuclear Management Partners LtdRegistered Office: Booths Park,Chelford Road, Knutsford, Cheshire WA16 8QZCompany Registration No. 1002607

Page 3 of 3programme. Sellafield Ltd will consult with the Agency on this allocation.To the south of Sellafield, beach monitoring has been carried out at Drigg beach each year,extending down to Drigg Point and the Ravenglass estuary. The HPA presentation to themulti-agency workshop in November 2010 included a recommendation for: “Further monitoringat Drigg beach, to reduce uncertainties in the assessment of the population of objects on thatbeach”. Consistent with this recommendation, Drigg beach will be monitored twice during2011/12.In developing this programme, Sellafield Ltd aims to deliver a schedule of beach monitoringthat achieves the right balance between beach locations and target areas; whilst recognisingthe range of stakeholder views on the monitoring operations themselves. We believe theprogramme is commensurate with the levels of risk as currently assessed; and is capable ofproviding reassurance that risks remain very low. As in previous years, where findings fromthe monitoring result in the need to review the programme, this will be done in full consultationwith the Agency.I look forward to your response.Yours sincerelyMartin EJ CloughEnvironmental Monitoring and AssessmentsEHS&Qmartin.clough@sellafieldsites.comOn behalf of Sellafield LtdCopied toRegulator Liaison Office, B113J DesmondA company owned by Nuclear Management Partners LtdRegistered Office: Booths Park,Chelford Road, Knutsford, Cheshire WA16 8QZCompany Registration No. 1002607

Week StartingSoftrak Beach MonitoringArea Targets(ha)Paymentin Period04-Apr Sellafield (a) 4 111-Apr25-Apr18-AprBuffer Time –202-May09-May Sellafield (b) 416-May St Bees (1) 423-MayVehicle Maintenance/Strandline30-May Drigg (1) 506-Jun Sellafield (c) 413-Jun20-JunBraystones (1) 14427-Jun04-Jul Sellafield (d) 411-Jul Seascale (1) 518-Jul St Bees (2) 425-Jul01-Aug08-Aug15-AugBuffer Time –22-Aug629-Aug05-Sep Sellafield (e) 412-Sep St Bees (3) 419-Sep Vehicle Maintenance/Strandlinee/Strandline26-Sep Seascale (2)503-Oct Sellafield lafield (f)4710-Oct Whitehaven en North/Harrington 417-Oct24-OctBraystones (2) 1830-Oct807-Nov14-Nov Sellafield (g) 421-Nov Whitehaven North/Harrington 428-Nov St Bees (4) 405-Dec Sellafield (h) 4912-Dec Allonby 419-Dec Vehicle Maintenance/Strandline –PropposeddChristmas Break02-Jan09-JanSt Bees (5) 816-Jan Sellafield (i) 323-Jan Investigation 430-Jan06-FebBraystones (3) 1413-Feb20-Feb Sellafield (j) 327-Feb Seascale (3) 405-Mar Drigg (2) 412-Mar Sellafield (k) 319-Mar Vehicle Maintenance/Strandline –26-MarBuffer TimeCumulative Totals ==>150 ha101112

BeachHectare CoverageSellafield 41Braystones 46St Bees 24Seascale 14Investigation 4Drigg 9Whitehaven/Harrington 8Allonby 4Total 150Proposed

Additional justification of 2011/12 Beach Monitoring ProgrammeThe proposed 2011/12 Beach Monitoring Programme was shared with theEnvironment Agency in a letter to Stuart Page on 11 February 2011. Theletter sets out proposals for a total of 150 hectares and identifies coverageand scheduling for each of the beach areas to be monitored. This notesupplements the letter by providing more detail on specific objectives of theprogramme and how these will be met.Based on the current information available, the Health Protection Agency riskassessment concludes that:“…the overall health risks to beach users is very low and significantly lowerthan other risks that people accept when using beaches, for example,drowning in UK coastal waters.”The primary objective of the ongoing programme is to ensure that furtherconfidence and reassurance can be given that overall risks to beach usersremain at or below those estimated in the HPA assessment. To achieve this,the programme will focus on: Trending of particle population changes with time, to understand therepopulation rates for individual beaches; and Improved understanding of the transport of material, in particular to thenorth beyond St Bees Head, to confirm the current spatial distribution.The probability of a member of the public encountering a find has beendetermined in the HPA risk assessment. The estimate requires understandingof: find population; habit data; and find activity profile. Whilst the currentestimate of risk is very low, to further reduce uncertainties the 2011/12programme will include re-visits to pre-determined areas on Sellafield,Braystones, St Bees and Seascale Beach, together with re-visits to beachesfurther afield, where low find rates have been recorded during previousmonitoring.The determination that a 150 hectare programme is appropriate is primarilydriven by the current understanding of risk and is an area that is consistentwith that specified for the first full year of monitoring achieved in 2007/08(146.7 hectares). In that year, and each subsequent year the total areamonitored has exceeded the target area; and a significant amount of data andinformation has been amassed. Building on the progress made in previousyears, the following sets out what the 2011/12 programme will focus on.The beaches selected specifically for repeat monitoring have been identifiedbased on a number of criteria:I. Areas of high find ratesa. Sellafield – highest find-rate beach

. Braystones – second highest find-rate beach, also withincreased occupancyII. Areas with high levels of public occupancya. St Bees and Seascaleb. BraystonesIII. Areas covered by extensive existing monitoring data (generallyconsistent with i and ii above)a. Sellafieldb. Braystonesc. St Bees and SeascaleIV. Areas of beach with consistent sand coverage (subject to seasonalvariations in depth)V. Areas with high confidence of monitoring repeatabilityFor each of these beaches, specified repeat area boxes have been identifiedas part of the respective beach monitoring total area.At Sellafield beach 2 areas (boxes) have been selected. These are both 1hectare in size and will be re-monitored eleven times each during theprogramme year. Selection of these areas has focussed on beach areas forwhich data has been collected in previous years monitoring (see table below)and where consistently high find rates have been observed. These boxesrepresent the core area to be covered on each and every visit to the Sellafieldbeach, with additional coverage of the neighbouring beach, up to a total of 4hectares dependent on available area at each monitoring visit. Thiscombination of core areas and additional area affords a degree of flexibility inthe monitoring and avoids overly constraining the contractor in what can bechallenging conditions.Likewise, at Braystones 2 box areas have been selected. These are larger insize (5 hectares) and will be revisited three times in the programme year. Aswith Sellafield, each of these areas has been revisited extensively in previousyears monitoring (see table below); and represent areas of elevated findrates. A total of 14 hectares will be covered on each visit to Braystones, toinclude both of the defined 5 hectare boxes.Both St Bees and Seascale are beaches that are regularly visited bymembers of the public. At each beach a single area (3 hectares) has beenselected, closest to the main parking areas and public access points. St Beeswill be revisited five times during the programme year, with Seascale revisitedthree times, reflecting the northerly bias to find rates. As detailed in the letterto EA, the visits to these beaches have been scheduled closely around theBuffer Time breaks, during which the highest occupancy levels are expected.A total area of 24 hectares will be covered at St Bees, with a total of 14hectares covered at Seascale.

In the context of the total monitoring, repeat areas represent approximately50% of the 150 hectare programme. Details of the repeat monitoring areasare summarised below and accompanying maps can be found in Appendix 1:Sellafield- 2 x 1 hectare boxesBraystones - 2 x 5 hectare boxesSeascale - 1 x 3 hectare boxSt Bees – 1 X 3 hectare boxThe box areas identified for repeat visits have each been monitoredpreviously in the past four years (some in part and some in their entirety),enabling year-on-year and seasonal change comparisons to be made overthe longest available time periods:Beach Monitoring Area Number of previousmonitoring visitsSellafield 1 (north) 9Sellafield 2 (south) 10Braystones 1 (north) 9Braystones 2 (south) 10Seascale 5St Bees 6The criteria used to select the beach areas to be monitored further afield arebroadly similar to those used for the repeat areas, as set out above. Thebeaches covered have generally lower occupancy and very low find rates.Drigg beach was identified in the HPA risk assessment as having a relativelyhigh uncertainty because of the large total area and the relatively lowcoverage achieved to date. Two return visits have been scheduled with atotal of 9 hectares targeted. The main aim here is to further reduce levels ofuncertainty.The beaches to the north of St Bees have generally low availability ofaccessible sand coverage until Allonby. However, to reflect the apparentdecrease in find rate as you move northwards, 8 hectares has been allocatedto Whitehaven/Harrington areas and a further 4 hectares has been allocatedto Allonby. The main aims here are again a reduction in uncertainty and alsoimproved understanding of particle transport.In addition, 4 hectares has been unassigned, to build flexibility into theprogramme and to allow Sellafield Ltd to respond to developments in both findrates and/or changes in occupancy.

Appendix 1:Maps of Proposed Repeat Monitoring Areas for Sellafield, Braystones,Seascale and St Bees