Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Abstract

The long-term issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive waste. Important radioactive wastes are minor actinides (MA: 237 Np, 241 Am, 243 Am, etc.) and long-lived fission products (LLFP: 129 I, 99 Tc, 79 Se, etc.). The purpose of this study was to show a system that can simultaneously achieve the breeding of fissile materials and the transmutation of MA and LLFP in one fast reactor. Transmutation was carried out by loading innovative Duplex type MA fuel in the core region and LLFP containing moderator in the first layer of the radial blanket. Breeding was achieved in the core and axial blanket. As a result, it was clarified that in this fast breeder reactor, a breeding ratio of about 1.1 was obtained, and MA and LLFP achieved a support ratio of 1 or more. The transmutation rate was 10.3%/y for 237 Np, 14.1%/y for 241 Am, 9.9%/y for 243 Am, 1.6%/y for 129 I, 0.75%/y for 99 Tc, and 4%/y for 79 Se. By simultaneously breeding fissile materials and transmuting MA and LLFP in one fast reactor, it will be possible to solve the long-term issues of the nuclear power reactor system, such as securing nuclear fuel resources and reducing radioactive waste.