As well as dominating the news headlines, the delays to EDF’s Hinkley Point C are also creating waves over 300 miles to the north at Sellafield and the fate of its stockpile of 140 tonnes of separated plutonium recovered from decades of spent fuel reprocessing. A Government decision on how this stockpile is to be dealt which has been expected for some time has been put back for a decade – until around 2025 at the earliest.
At a meeting on the 27th April of the Spent Fuel and Nuclear Materials Working Group (a sub-group of West Cumbria Sites Stakeholder Group WCSSG) the NDA outlined why it was now considered the UK Government was unlikely to come to a decision on the stockpile much before 2025. The reasoning behind the NDA’s projection is that the Government’s currently preferred option of re-using plutonium as Mixed Oxide (MOX) fuel envisages the fuel being used in UK’s fleet of new-build reactors. Given that the first of these would not realistically be in operation until 2025 at the earliest – and would then need to operate for up to 10 years to reach a ‘steady state’ burning conventional uranium fuel,- any decision by the operator in favour of using MOX was unlikely to be made until 2035. To contemplate building a new commercial MOX plant (last estimated at £5Bn-£6Bn by the NDA in 2011) before new-build reactors were up and running and a firm interest in using MOX fuel shown by their operators would represent poor business practice.
Options on how to manage Sellafield’s plutonium stockpile have been the subject of numerous consultations since the NDA launched a Plutonium Options – for Comment Paper in 2008, The Government, via its first public consultation in 2011 which looked at three’ high level’ management options (plutonium re-use, its immobilisation for direct disposal and its long-term storage at Sellafield) concluded that its preferred option was to re-use the material as MOX fuel. That preference remains today despite the belated addition to the list in 2012 by the NDA of two new options – a proposal by GE Hitachi to get rid of the plutonium through a PRISM fast reactor to be built at Sellafield and a proposal by Candu Energy to burn it in its Enhanced Candu 6 reactors (EC6) as Canmox.
Originally ruled out by NDA and Government, the re- emergence of the fast reactor proposed by GE Hitachi as a new contender appears to have triggered a similar revival of official interest in immobilisation, with an emphasis on the Hot Isostatic Press (HIP) process that converts plutonium under high pressure and temperature into a ceramic waste form. With the indefinite storage of plutonium at Sellafield ruled out as a long-term credible option, the NDA’s latest assessment of all options – GE Hitachi’s Prism, Candu’s Canmox, Areva’s MOX ‘Convert Project’ and immobilisation – was submitted to Government in December 2015 and details of that assessment are expected to be published by the NDA in July this year in the form of an updated Position Paper.
Members of last week’s Working Group were also advised that all options still required to be progressed ‘proportionately’ – including the scaling up of the existing test-lab HIP immobilisation process to a viable commercial scale and, in the continued absence worldwide of an operating PRISM fast reactor, gaining greater confidence in GE Hitachi’s proposal.