Exploratory neutronic evaluation on the enhancement of tritium breeding and energy multiplication capability using (Th,U)O2 in a solid-state tritium breeding blanket of a fusion demonstration reactor

Abstract

The achievable tritium breeding ratio (TBR) in Korean fusion demonstration reactor (K-DEMO) that utilizing the deuterium-tritium nuclear fusion reaction for energy production is the critical design parameter for the self-sufficiency of tritium. However, the calculation uncertainty of the achievable TBR makes it difficult to fully understand the tritium fuel cycle in the K-DEMO. Moreover, if the achievable TBR is less than the required TBR, the calculation uncertainty of the achievable TBR makes the design limitation on the self-sufficient tritium supply of the K-DEMO. Therefore, making the achievable TBR larger than the required TBR is the most important goal of the K-DEMO design for the self-sufficient tritium supply. To create an achievable TBR with a margin greater than the required TBR, the modified neutron-multiplying material that is different from the typical neutron-multiplying material (9Be) is tested in this study. The blending of the fissionable (232Th) and fissile (233U) material with 9Be is attempted to enhance the neutron multiplication reaction resulting in a gradual increase of the achievable TBR according to the increase of the atomic faction of fissile material. With the addition of fissile material, it is found that energy multiplication accompanied by fission reaction is dramatic. The possibility of the self-breeding of 233U from 232Th is also justified. However, the neutronic damages resulting in the frequent replacement of the components in the tritium breeding blanket and generation of the high-level waste also occurred as the negative impact accompanied by the blending of 232Th and 233U with 9Be.