Effects of irradiation and implantation on permeation and diffusion of hydrogen isotopes in iron and martensitic stainless steel

Permeation and diffusion of hydrogen were measured on virgin and preirradiated iron and martensitic stainless steel with thicknesses of 210 and 810 mu m at temperatures from 100 degrees to 400 degrees C. A slight dependence of permeability on thickness and pressure was tentatively ascribed to surface effects. Pressure dependence of diffusivity and deviation from Arrhenius behaviour at low temperatures and/or small thicknesses was consistently described by a model of hydrogen trapping at saturable traps, Preirradiation at room temperature to displacement closes up to 1.5 x 10(-3) dpa had no influence on permeation but reduced the diffusivity in the steel. Diffusion coefficients were also derived from the time dependence of hydrogen release during implantation. The results show significant differences to the results from permeation measurements. Permeation was strongly increased under penetrative light ion irradiation, probably due to ionization and dissociation of the hydrogen gas on the upstream side.