2009 Report to Government on National Research and

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containers is one of several which may offer more flexibility in terms of s<strong>to</strong>rage and disposal options but it is at an early stage of development in the UK context. Other research and development issues for s<strong>to</strong>rage systems brought <strong>to</strong> our attention in meetings with NDA, SLCs, British Energy and at the IoP S<strong>to</strong>rage R&D meeting (CoRWM doc. 2519) include: • Especially for older existing s<strong>to</strong>res, how do we make better predictions of their lifetimes, how can ventilation systems be improved, how can conditions in the s<strong>to</strong>re be better moni<strong>to</strong>red and better arrangements be introduced for inspecting waste packages? • For future s<strong>to</strong>res, who is performing R&D on the newer mini-s<strong>to</strong>re concept now being considered? • If Scotland plans extended near-site, near-surface s<strong>to</strong>rage as an option in its own right then R&D will be needed <strong>to</strong> develop appropriate concepts and detailed designs. A.17 The first point is highlighted in paragraphs 3.36-3.38 of the CoRWM Interim S<strong>to</strong>rage report (CoRWM doc. 2500) which covers the lack of suitable atmosphere control in some older s<strong>to</strong>res. This has led <strong>to</strong> waste container corrosion that is faster than that envisaged when the LoC was issued, due in large part <strong>to</strong> salty coastal atmospheres. As a result it is more likely that remedial action (e.g. overpacking will eventually be needed prior <strong>to</strong> waste transport and disposal. There is a need <strong>to</strong> assess options for improving ventilation systems and for moni<strong>to</strong>ring atmospheric conditions in s<strong>to</strong>res where such conditions exist or could occur in future. It is also essential that new s<strong>to</strong>rage systems are designed with appropriate ventilation and atmosphere moni<strong>to</strong>ring provisions. They should also have appropriate arrangements and regimes for moni<strong>to</strong>ring and inspecting waste packages. The industry recognises it is not able <strong>to</strong> carry out more than very limited inspection on ILW packages in some s<strong>to</strong>res and that R&D is required <strong>to</strong> develop remote moni<strong>to</strong>ring and inspection techniques (CoRWM doc. 2630). Some of these points are recognised in the NDA UK s<strong>to</strong>rage review (NDA, <strong>2009</strong>d). A.18 Further R&D is needed <strong>to</strong> demonstrate that existing s<strong>to</strong>res will achieve the design lives claimed for them and <strong>to</strong> assess whether these lives can be extended, and if so by how much. If controlled atmosphere s<strong>to</strong>res are <strong>to</strong> be required for many decades, R&D in<strong>to</strong> atmosphere-independent packages (such as ceramic overpacks) may be needed. The option of using of such packages could then be compared with the controlled atmosphere option. Management of Spent Fuels A.19 The existing and committed UK inven<strong>to</strong>ry of spent or used nuclear fuels can be divided in<strong>to</strong> categories depending on type and source. The categories are: Magnox fuel, advanced gas cooled reac<strong>to</strong>r (AGR), pressurised water reac<strong>to</strong>r (PWR) fuel, “exotic” fuels and MoD fuels. The current management strategy for each is summarised below along with the related current and planned R&D and areas in which further R&D is likely <strong>to</strong> be needed are highlighted. An option related <strong>to</strong> the long-term management of spent fuels that is rapidly gaining favour is dry s<strong>to</strong>rage and R&D issues connected <strong>to</strong> this are also identified below. CoRWM Document 2543, Oc<strong>to</strong>ber <strong>2009</strong> Page 102 of 151
Magnox Fuel A.20 Magnox fuel consists of uranium metal in a magnesium-alloy cladding. The NDA's current strategy, as embodied in the Magnox Operating Plan, MOP8 (NDA, <strong>2009</strong>e) is <strong>to</strong> reprocess all spent Magnox fuel. The UK Inven<strong>to</strong>ry indicates that around 5,800 <strong>to</strong>nnes (heavy metal, tHM) of Magnox fuel remains <strong>to</strong> be reprocessed (Defra/NDA, 2008b). Some of it is in operating reac<strong>to</strong>rs, some in temporary dry s<strong>to</strong>rage in shut-down reac<strong>to</strong>rs and in the Wylfa dry s<strong>to</strong>re, and the rest is s<strong>to</strong>red under water, mainly at Sellafield. The reprocessing strategy is contingent upon the Sellafield Magnox Reprocessing Plant continuing <strong>to</strong> operate until all Magnox spent fuel that can be reprocessed has been. Given the elderly nature of the Magnox Reprocessing Plant, considerable effort and resource is being expended on keeping it operating but the possibility of chronic or acute failure before reprocessing is completed (currently projected as 2016) must be considered (CoRWM doc. 2520). A.21 Accordingly, contingency plans for any un-reprocessed Magnox fuel are required (CoRWM doc. 2520). The NDA is investigating these (NDA, 2008d; CoRWM docs. 2418, 2500, 2624) along three principal lines, namely: • Reprocessing through the Thermal Oxide Reprocessing Plant (THORP) with the recovered uranium and plu<strong>to</strong>nium and the associated HLW being managed in the same way as other THORP products. This would be difficult and costly, entailing modification <strong>to</strong> the THORP head end, and would require significant R&D for the necessary adaptations of the THORP process. It would also disrupt and prolong the THORP programme. For these reasons this option is currently 'shelved' by the NDA. • Dry s<strong>to</strong>rage followed by geological disposal. This necessitates drying the spent fuel before placing it in one of the preferred forms of dry s<strong>to</strong>rage (para A.34). An issue is how dry <strong>to</strong> make the fuel. There is at present no capability in the UK for drying spent fuel of any kind on a large scale but there is considerable experience in other countries. The work at Hanford in the USA, where metal fuels have been successfully dried as a prelude <strong>to</strong> dry s<strong>to</strong>rage and eventual disposal, is of relevance <strong>to</strong> Magnox fuel. Although the Hanford process has been shown <strong>to</strong> be viable, even for seriously corroded fuel elements, it is unlikely it could be transferred <strong>to</strong> the UK for Magnox fuel without substantial R&D (CoRWM doc. 2520). The Hanford experience is with smooth zircaloy clad metal fuel. In contrast, Magnox fuel cladding has large fins which result in a much higher surface area. Magnox fuel cladding is considerably more reactive than zircaloy and hence is much more susceptible <strong>to</strong> corrosion in water. In addition, carbonaceous deposits, which may be particularly difficult <strong>to</strong> dry out, are often found on Magnox fuel. Due <strong>to</strong> the potential for continued reactivity of uranium metal further R&D would be needed on packaging the dried product for s<strong>to</strong>rage and geological disposal in a UK facility (CoRWM doc. 2500). Our understanding is (CoRWM docs. 2418, 2523, 2624) that the NDA is funding some R&D in<strong>to</strong> the drying of Magnox fuel and in<strong>to</strong> packaging it for disposal, and will evaluate this option shortly with a view <strong>to</strong> pursuing it further. • Encapsulation in preparation for interim s<strong>to</strong>rage and geological disposal. Experience with encapsulation of relatively small amounts of reactive metals such as uranium has shown that existing cement formulations would not be CoRWM Document 2543, Oc<strong>to</strong>ber <strong>2009</strong> Page 103 of 151
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Committee on Radioactive Waste Mana
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Finland ...........................
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Geosphere Characterisation ........
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EXECUTIVE SUMMARY 1. CoRWM’s remi
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odies would need to</strong
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disseminate and assimilate its resu
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1.3 CoRWM’s Work Programme for 20
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1.11 The R&D requirements for the l
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2. ESTABLISHING R&D REQUIREMENTS Wh
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adioactive waste management facilit
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should mitigate the risks of findin
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there is no unwarranted repetition
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safety case development, the overal
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Table 1. Approximate annual levels
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Figure 1. Structure of UK R&D provi
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NDA R&D for Geological Disposal 3.1
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3.27 The purpose of NNL can be summ
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identified the research required an
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submitted to RCEP
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Box 1. Research Council Funded Univ
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3.62 BGS is conducting three projec
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3.70 In the current FP7 programme (
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3.77 RCEP noted that there was a la
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sectors: land disp
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eyond those that RWMD intends <stro
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Page 149 and 150: RS Royal Society RSC Royal Society
Page 151: ACKNOWLEDGEMENTS Leadership in the
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2009 Report to Government on National Research and

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