Three-dimensional neutronic calculations for some fluid material optimizations in a fusion-fission hybrid reactor by using Monte Carlo method

In this study, an APEX hybrid reactor was designed using APEX fusion technology. In the designed APEX hybrid reactor 10% UC2, 10% ThC2 and fluid consisting of 0.1-1% AmF3, 0.1-1% CmF3, 0.1-1% NpF4 heavy metal with 89.9-89% Li20Sn80 molten salt mixture, Ferritic Steel (9Cr2WVTa) structural material, reflective Beryllium was used. The neutron wall load of the reactor at the first liquid wall was designed to be 10 MW/m2, the second liquid wall thickness was 50 cm, and the fusion power was 4000 MW. MCNPX-2.7.0 Monte Carlo code and ENDF/B-VIII.0 nuclear reaction cross-sectional library were used in the three-dimensional design of the reactor and in the neutronic calculations in the respective regions. The Neutron Flux, Tritium Production Rate (TBR), Energy Multiplication Factor (M), Heat Energy, Fission Reaction Number and Fissile Fuel Production were calculated for first liquid wall, the second fluid wall, armor zones of the reactor. Proton production, deuterium production, tritium production, 3He production, 4He and DPA (displacement per atoms) values were calculated as the radiation damage parameters of 30 full power years (FPY) in the steel region which is the structural material of the reactor. In the designed model, it was observed that when the ratio of heavy metal was increased in the fluids selected in the first liquid wall, second liquid wall and armor regions and the melt salt ratio was decreased, the increased in the Am and Cm fluids decreased in the Np fluid. The essential condition TBR> 1.1 for the self-sufficiency of tritium and the required condition M> 1.2 for the thermal power was provided for the selected fluids, the structural material and the reflector. In the study, TBR values decreased as the ratio of AmF3 and NpF4 increased, it was observed that when the decrease in the Li ratio in the selected fluids decreased, the TBR was decreased and the TBR value increased as the CmF3 ratio increased. The increase in the ratio of AmF3, CmF3 and NpF4 was observed M and heat energy increased. It was observed that the values of neutron flux, heat deposition energy, fission energy and fission reaction number decreased exponentially from the plasma to the outer region of the reactor. It was determined that the reaction in the reactor (n,γ) was effective on fissile fuel production and 239Pu and 233U fissile fuel were produced from 238U and 232Th fertile material. In the structural material of neutrons (n, p), (n, d), (n, t), (n, 3He), (n, 4He), DPA reactions were determined to cause radiation damage.