The potential impact of fast reactors and fuel recycling schemes on the UK's nuclear waste inventory

  • Matthew Gill

Student thesis: Phd


This work considers the impact of fast reactor fuel cycles on the UK's nuclear waste inventory, focusing on the disposition of the UK's plutonium stockpile and spent fuel from new build nuclear reactors. Reprocessing spent fuel from nuclear reactors has led to a large stockpile of civil plutonium in the UK. At the end of reprocessing the stockpile was estimated to be 112 tonnes. This large stockpile of separated plutonium poses a proliferation concern and there is no strategy at present for UK plutonium disposition. The NDA's position paper in 2014 stated the re-use of plutonium in a reactor as a preferred option. These options included Mixed OXide (MOX) fuelled Pressurised Water Reactors (PWR) and the use of plutonium in a Sodium-cooled Fast Reactor (SFR), PRISM, operated as a once-through plutonium burning fast reactor. As yet a preferred option has not been selected by the government.Nuclear power is the UK's largest source of low-carbon electricity. Current plans aim to build 16 GWe of new reactors by 2050 to replace the UK's current fleet.This work considered PWR MOX and once-through SFRs for UK plutonium disposition, comparing their relative merits to the direct disposal of the plutonium stockpile in a geological repository. The waste performance of disposition options were compared using assessment criteria based on: Technology Readiness Level (TRL), final stockpile mass, repository size and radiotoxicity. To maximise the reduction of the UK's plutonium stockpile, closed SFR fuel cycles were also considered with scenarios aimed at improving waste performance. Once-through and closed SFR fuel cycles were also considered for the disposition of spent fuel from new build reactors.Research presented in this thesis shows that UK waste disposition options are highly dependent on fuel cycle operating parameters. In once-through plutonium disposition options all scenarios increased repository size compared to direct disposal. Once-though SFRs increased repository size the least, where as PWR MOX reduced the stockpile mass most significantly. The most significant improvement in waste performance, using a closed fuel cycle up to 2150, required short reprocessing times and americium reprocessing. There were no additional improvements of significance with curium reprocessing and the choice of metallic or MOX fuelled SFRs had little impact on waste performance. Preferred fuel cycle scenarios are dependent on the priority given to different assessment criteria. To compare fuel cycle scenarios on an even basis, decision analysis methods were presented using assessment criteria results from the fuel cycles modelled in this work. Decision analysis methods were designed so that the reader can apply their own priorities, through the use of weightings, to the assessment criteria to determine preferable fuel cycle scenarios.
Date of Award1 Aug 2016
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorTimothy Abram (Supervisor) & Gregg Butler (Supervisor)


  • Plutonium stockpile
  • SFR
  • Plutonium disposition
  • UK plutonium
  • UK fuel cycle
  • Fast reactor
  • Fuel cycle
  • Plutonium

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