Modeling experimental dependencies of deuterium penetration through SS316IG stainless steel under reactor irradiation conditions

• Neutron irradiation significantly slows deuterium permeation in SS316IG steel. • Permeation kinetics are governed by reversible radiation-induced traps below 450 °C. • Oriani model reproduces steady-state flux reduction under irradiation. • Deuterium trapping is diffusion-limited, while detrapping is thermally activated. This paper presents an analysis of the results of reactor experiments on deuterium permeation in SS316IG steel, performed at sample temperatures of 350–550 °C, with an inlet deuterium pressure of approximately 500 Pa and a thermal neutron flux of ∼ 2·10 13 n/cm 2 ·s. Based on a diffusion model with traps in the quasi-equilibrium (Oriani) approximation, the effect of neutron irradiation on the kinetics of deuterium permeation was analyzed, and the effective parameters of radiation-induced traps were determined for sample temperatures below 450 °C. The trap concentration values obtained at temperatures of 350 °C (0.83 mol/m 3 ) and 400 °C (0.5 mol/m 3 ) were found to be more robustly determined than the parameters of the Arrhenius dependence of the trapping equilibrium constant. The combinations of the pre-exponential factor K 0 and the binding energy E b were found to lie in the ranges K 0 ≈0.02–0.3 mol/m 3 and E b ≈5–20 kJ/mol. The results obtained contribute to the refinement of models describing hydrogen isotope transport in fusion reactor structural materials and can be used to predict their behavior under realistic operating conditions.