Assessment of the Equilibrium State in Reactor-based Plutonium or Transuranics Multi-recycling

An assessment of the radiotoxicity of spent nuclear material and the fuel handling issues associated with plutonium (Pu) or transuranics (TRU) multi-recycling in PWRs using the CORAIL assembly concept has been performed. This necessitated the development of an analytical approach to solve directly for the equilibrium state of repeated recycle, including higher actinide content. The equilibrium states used in the assessment are determined by a one-group transmutation code with cross sections prepared by the WIMS8 code (for transuranics below Cm) and ENDF/B-V data (for Cm and above). The fuel handling indices suggest that Pu multi-recycling is feasible. However, the high radiotoxicity of the spent assembly content suggests that Pu multi-recycling would provide only minimal benefits to the repository if the goal is to reduce the radiotoxicity of the disposed waste to less than that of the source uranium used in producing the fuel in a thousand years. TRU multi-recycling is the most beneficial to the repository because the amount of TRU in the disposed waste is significantly reduced by keeping the TRU in the PWR fuel cycle. However, TRU multi-recycling in the CORAIL or alternative assembly designs will complicate fuel handling at the separation, fabrication, and core loading stages, due to the high spontaneous fission neutron emission rates of the higher actinides.