Benchtop Zone Refinement of Simulated Future Spent Nuclear Fuel Pyroprocessing Waste

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  • Mark Ogden
  • Paul Bingham
    Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
  • Alex Scrimshire
    Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
  • Daniel Backhouse
    Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
  • Deng Wei
    Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
  • Clint Sharrad
    Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
  • Colleen Mann
    The Henry Royce Institute and Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD, UK
  • Mike Harrison
    National Nuclear Laboratory, Sellafield, Seascale, Cumbria CA20 1PG, UK
  • Donna McKendrick
    National Nuclear Laboratory, Sellafield, Seascale, Cumbria CA20 1PG, UK
The UK’s adoption of pyroprocessing of spent nuclear fuel as an alternative to the current aqueous processing routes requires a robust scientific underpinning of all relevant processes. One key process is the clean-up of the contaminated salt from the electroreducing and electrorefining processes. A proposed method for this clean-up is zone refining, whereby the tendency of the contaminants to remain in the liquid phase during melting and freezing is exploited to ‘sweep’ the contaminants to one end of the sample. Experiments were performed, utilising off-the-shelf laboratory equipment, to demonstrate the feasibility of zone refining for clean-up of electroreducing and electrorefining wastes. This was successful for the electrorefining simulant samples, with effective segregation coefficient, keff, values, which provide a measure of the degree of separation in the sample, between 0 and 1. Lower values indicate greater separation, with values of as low as 0.542 achieved here, corresponding to a reduction in RECl3 content from 10.0 wt.% to 8.4 wt.% (for 80% salt reuse). Due to difficulties in obtaining a fully homogeneous electroreducing simulant waste, it was not possible to demonstrate the feasibility of zone refining using the current experimental setup. Further research is required to elucidate the correct preparation conditions for production of homogeneous electroreducing waste simulants.

Keywords

  • pyroprocessing, zone refinement, chloride salts, LKE, nuclear fuel cycle, molten salt
Original languageEnglish
Pages (from-to)1781
JournalMaterials
Volume17
Issue number8
DOIs
Publication statusPublished - 12 Apr 2024
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