Long-life fast breeder reactor with highly protected Pu breeding by introducing axial inner blanket and minor actinides

Abstract

A feasibility study on simultaneous approaches to the extension of core life-time and the high protected plutonium (Pu) breeding by introducing the axial inner blanket and doping minor actinides (MAs) in a large-scale sodium-cooling fast breeder reactor (FBR) has been performed for mix-oxide (MOX) and metallic fuel. The maximum available effective full power days (EFPDs) in MOX-fueled FBR with introducing the axial inner blanket and MA was extended from 1700 to 2900 compared with the conventional MOX-fueled FBR. The maximum available EFPDs in the case of metallic-fueled FBR with introducing the axial inner blanket and MA was extended to 5900. Conventional Attractiveness (ATTR) to evaluate the proliferation resistance of Pu based on isotopic material barriers such as decay heat (DH) and spontaneous fission neutron rate (SN) was modified by taking into account bare critical mass (BCM) as Attractivenessmod (ATTRmod), which was applied to evaluate the proliferation resistance of Pu generated in the axial inner blanket and axial/radial outer blankets. It was found that if only a small amount (4–5wt.%) of MA are doped into the axial inner blanket and axial/radial outer blanket in both MOX and metallic fuel, the proliferation resistance of Pu was increased to satisfy the criteria of “practically unusable for an explosive device” proposed by Pellaud and “technically unfeasible for a high-technology hypothetical nuclear explosive devices (HNEDs)” proposed by Kessler and Kimura. The fissionable Pu inventory ratio (FPIR), defined as the ratio of inventory of 238Pu, 239Pu and 241Pu at the beginning of cycle (BOC) to that at the given irradiation time, was introduced to survey the breeding characteristics of FBR. FPIR at the end of cycle (EOC) in MOX-fueled FBR with doping MA into the axial inner blanket and axial/radial outer blankets was increased from 1.008 to 1.168 compare with the conventional MOX-fueled FBR. In addition, FPIR at EOC in metallic-fueled FBR with doping MA into the axial inner blanket and axial/radial outer blankets was increased to 1.263. In the present study, the feasibility of simultaneous approaches to the extension of core life-time and the high protected Pu breeding has been confirmed by the introduction of the axial inner blanket and MA doping.