Material Attractiveness Evaluation Of Actinides In Pyroprocessing Facility For Partitioning And Transmutation Cycle

Research and development of partitioning and transmutation (P&T) cycle with accelerator-drive systems (ADSs) transmuting minor actinides (MAs) separated from the commercial cycles has been continuously conducted to reduce the high-level radioactive waste (HLW) contained in spent fuel discharged from nuclear power plants. The Japan Atomic Energy Agency has proposed a pyrochemical process for reprocessing ADS spent fuel with high decay heat and radioactivity due to the large amount of MA. Since the chemical form and composition of the fuels are different from those of the current commercial cycles, it is necessary to examine the detection accuracy of the safeguards (SGs) and the design level of physical protections (PPs) which are required for the P&T cycle. In this study, material attractiveness of actinides in the pyroprocessing facility was evaluated and it was compared with that of the MOX fuel assemblies (fresh and spent fuels) for a conventional boiling water reactor (BWR). For example, the Cd cathode used to recover actinides from ADS spent fuel by molten salt electrolysis in the pyroprocessing facility of P&T cycle was less attractive than the MOX fuel assembly for the BWR because the recovered actinides in the Cd cathode were composed of some nuclides with high decay heat such as 238Pu and 244Cm. From the results of the attractiveness evaluation in this study, it was clarified that the SG detection accuracy and PP design level for pyroprocessing facility of P&T cycle would be sufficient to be equal to or lower than those of BWR facility.