An innovative fast reactor core design for rapid reduction of separated Pu and its proliferation concerns

Abstract

This report examines a proposed innovative fast reactor (FR) core design that enables rapid reduction of separated plutonium (Pu), while presenting the equivalent or, in some cases, even better operation and safety performance compared to a typical FR. The impact of the innovative core design was evaluated based on mass balance and non-proliferation features.The fundamental characteristics of FRs for the rapid reduction of separated Pu indicate that a core design with the blanket fuel regions removed and a higher-enriched mixed oxide (MOX) fuel loaded in the core regions should result in the highest Pu loading and Pu reduction ratio. Furthermore, three approaches of the age impact of MOX fuel, the placement of gas plenum in the axial blanket and Pu enrichment zoning gradually dense in the outer core were comprehensively examined for operation and safety performance. These led to be higher Pu loading and Pu reduction with the requirements of a typical FR.In the mass balance and non-proliferation evaluation, it was clarified that the proposed FR had higher speed of separated Pu reduction than the light water reactor (LWR) or long storage. Consequently, the MOX fuels irradiated in the FR and the LWR were the downgraded categories in the nuclear security and safeguards regulations, which was the same as those of conventional spent nuclear fuel that exists abundantly worldwide.