Conceptual core design to transmute long-lived radioactive nuclides in a large fast breeder reactor

Analyses are performed to study the feasibility of transmuting long-lived radioactive nuclides such as long-lived fission products (LLFPs) in a large fast breeder reactor (FBR). The excess neutrons generated in the FBR core are fully utilized, not only to generate the fissile material, but also to transmute the LLFPs. The fission product target assemblies which consist of selected LLFPs, namely Se-79, Tc-99, Pd-107, I-129 and Cs-135, are loaded into the radial blanket region, so the self-generated LLFPs are transmuted by the FBR itself without significant influence on the nuclear and safety characteristics. The approach has a good potential applicability to future nuclear cycles such as the multi-recycling system in which long-lived radioactive waste is confined and reduced in volume. This study was sponsored by the Ministry of International Trade and Industry. (author)