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

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