In this study, the effect of the radiation damage of spent fuel-grade plutonium content was investigated in the structural material of a designed fusion-fission hybrid reactor system. In this study, the molten salt-heavy metal mixtures 99-95% Li20Sn80-1-5% SFG-Pu, 99-95% Li20Sn80-1-5% SFG-PuF4, and 99-95% Li20Sn80-1-5% SFG-PuO2 were used as fluids. The fluids were used in the liquid first-wall, blanket and shield zones of the designed hybrid reactor system. Four centimeter thick 9Cr2WVTa ferritic steel was used as the structural material. Proton, deuterium, tritium, He-3 and He-4 gas production rates are the parameters of radiation damage. In this study, damage to the total structural material and each 1.0 cm thickness thereof was measured as a function of radiation energy, using the selected fluid rates, for 30 full power years (FPYs). Three-dimensional analyses were performed using the most recent MCNPX-2.7.0 Monte Carlo radiation transport code and the ENDF/B-VII. 0 nuclear data library.