An optimization study of structure materials, coolant and tritium breeding materials for nuclear fusion-fission hybrid reactor

The blanket materials were evaluated and optimized for use in a nuclear fusion-fission hybrid reactor by calculating the tritium breeding ratio (TBR), the ratio of thermal power output to fusion power input (Q value) and the temperature distributions. The calculation of TBR and Q value was performed by Monte Carlo code (MCNP-4C) and the temperature distributions by one dimensional heat equation. First, the structure materials, coolant and tritium breeding materials were investigated in terms of the TBR and the Q value. Secondly, the layer structure was optimized by calculating the temperature distributions in the blanket where the materials were selected by considering the former results of the TBR and Q value. As a result, the highest TBR and Q value could be obtained, if vanadium alloy structure material, helium gas coolant and molten salt tritium breeding material would be used as the blanket material. In addition, by optimizing the blanket structure using these materials, it would be possible to get a high TBR of 2.0 maintaining the temperature limit of the blanket materials, and about twenty times the thermal power output could be produced compared to the fusion power input under the condition of effective multiplication factor of 0.80. (author)