Neutronic study on the effect of first wall material thickness on tritium production and material damage in a fusion reactor

In this study, the effects of changing first wall materials and their thicknesses on a reactor were investigated to determine the displacement per atom (DPA) and gas production (helium and hydrogen) in the first wall, as well as the tritium breeding ratio ( TBR ) in the coolant and tritium breeding zones. Therefore, the modeling of the magnetic fusion reactor was determined based on the blanket parameters of the International Thermonuclear Experimental Reactor (ITER). Stainless steel (SS 316 LN-IG), Oxide Dispersion Strengthened Steel alloy (PM2000 ODS), and China low-activation martensitic steel (CLAM) were used as the first wall (FW) materials. Fluoride family molten salt materials (FLiBe, FLiNaBe, FLiPb) and lithium oxide (LiO 2 ) were considered the coolant and tritium production material in the blanket, respectively. Neutron transport calculations were performed using the well-known 3D code MCNP5 using the continuous-energy Monte Carlo method. The built-in continuous energy nuclear and atomic data libraries along with the Evaluated Nuclear Data file (ENDF) system (ENDF/B-V and ENDF/B-VI) were used. Additionally, the activity cross-section data library CLAW-IV was used to evaluate both the DPA values and gas production of the first wall (FW) materials. An interface computer program written in the FORTRAN 90 language to evaluate the MCNP5 outputs was developed for the fusion reactor blanket. The results indicated that the best TBR value was obtained for the use of the FLiPb coolant, whereas depending on the thickness, the first wall replacement period in terms of radiation damage to all materials was between 6 and 11 years.