Abstract
The manufacture of a simulant UK Advanced Gas Cooled Reactor (AGR) spent nuclear fuel (SIMFuel) was achieved by Hot Isostatic Pressing (HIP). Characterisation of HIP AGR SIMFuels, tailored to burn ups of 25 GWd/t U and 43 GWd/t U (after 100 years cooling) demonstrated fission product partitioning, phase assemblage, microstructure and porosity in good agreement with spent nuclear fuels and SIMFuels, and AGR fuels in particular. A pivotal advantage of the application of the HIP manufacturing method is the retention of volatile fission products within the resultant SIMFuel as the result of using a hermetically-sealed container. This new approach to SIMFuel manufacture should enable the production of more accurate spent nuclear fuel surrogates to support research on spent fuel management, recycle, and disposal, and the thermal treatment of fuel residues and debris.
Highlights
The safe management and disposal of spent nuclear fuel is a critical challenge for nation states exploiting civil nuclear energy and the current global inventory of spent nuclear fuels exceeds 300,000 metric tonnes of heavy metal [1,2]
We considered that retention of the volatile fission product inventory in SIMFuel materials could be achieved under conditions of Hot Isostatic Pressing (HIP), in which reactive sintering is typically achieved in a hermetically-sealed stainless steel can, under high temperature and pressure [9]
The porosity of the SIMFuel determined by image analysis, using ImageJ software, are reported in Table 2, together with that determined for real Advanced Gas Cooled Reactor (AGR) spent nuclear fuel
Summary
The safe management and disposal of spent nuclear fuel is a critical challenge for nation states exploiting civil nuclear energy and the current global inventory of spent nuclear fuels exceeds 300,000 metric tonnes of heavy metal [1,2]. We considered that retention of the volatile fission product inventory in SIMFuel materials could be achieved under conditions of Hot Isostatic Pressing (HIP), in which reactive sintering is typically achieved in a hermetically-sealed stainless steel can, under high temperature and pressure (for fabrication of radioactive wasteforms: 1250oC and 200 MPa Ar) [9]. Our development of this technology for the thermal treatment of radioactive wastes has exploited this advantage to contain volatile radionuclide constituents within the product wasteform. For the purpose of this feasibility study, a simplified SIMFuel chemistry was used, with the focus on understanding the retention of Cs, Te and Mo as volatile fission products of interest
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