The parameters of gas-metal interaction solubility S, diffusivity D and permeability of protium and deuterium in stainless steel 316L have been determined in the temperature range from 600 to 900 K and in the pressure range from 102 to 105 Pa. The results can be presented by: where KS (Sieverts' constant) is given in Pa−1/2, D in m2.s−1, in m2.s−1.Pa−1/2, Po in Pa, T in K and R = 8.31 J.g-atom−1.K−1. The tritium properties have been calculated by application of quantumstatistical partition functions to the solution and diffusion process: The characteristic temperatures of vibration in the ground state, θ = hv/k and in the activated state, θ* = hv*/k have been determined from the measured ratios of protium and deuterium solubilities and diffusivities: