Investigation on the Nuclear Heat Deposition of Shielding Blanket for CFETR Phase I

China Fusion Engineering Test Reactor (CFETR) will be a steady-state fusion power plant using a tritium blanket system. The current challenge is to develop a shielding blanket (SB) system which shields the components from nuclear heat impact. In this article, neutronics issues on the nuclear heat deposition induced by neutrons and photons are studied. It is found that the nuclear heat in the SB modules of breeding regions are 0.04-0.12 W/cc, and it is increased to 0.08-0.115 W/cc in the divertor region. This indicates that the SB concepts in different regions lead to the same effect on nuclear heat deposition. Moreover, it indicates that the nuclear heat trends on the two kinds of particles present a shrunken trumpet distribution in an SB interior and finally could be reduced to the minimum. In particular, the different nuclear heat levels are due to the different materials used in the components, while the steel zones absorb more photon heat than neutron heat and water zones absorb more energy from neutrons than steel. In addition, the thermal-hydraulics issues are discussed based on the computational fluid dynamics (CFD) technology. This article clarifies the nuclear heat distribution issues and also proposes an approach toward heat removal exploration, which would be beneficial to the SB design concepts in the blanket engineering phase later.