Basic Analysis on Isotopic Barrier of Material Attractiveness Based on Plutonium Composition of FBR

Abstract

Fuel behaviors of the large fast breeder reactor have been investigated, as well as material attractiveness based on isotopic plutonium composition for evaluating proliferation resistance with regards to a combined evaluation of decay heat and spontaneous fission neutron barrier as key parameters of isotopic material barrier. Trans-uranium fuel (TRU) (MA + U-Pu) in the core regions and MA doping (MA + natural U) in the blanket regions as options of MA loading produce a higher Pu-238 composition for denaturing plutonium, which mainly comes from converted Np-237. The isotopic plutonium composition of TRU fuel is relatively less than the Pu composition of MOX fuel except for the Pu-238 composition that is higher than that of MOX fuel. MA in the core or blanket regions, which produces a higher Pu-238 composition, plays a key role in obtaining a high-level material barrier of decay heat and spontaneous fission neutron compositions. The material attractiveness level of plutonium composition in the core regions can be categorized as practically unusable and its level becomes less by adopting TRU fuel. In addition, the material attractiveness level in the blanket regions as being practically unusable can be reached from weapon grade by loading MA at a 2% doping rate.