AbstractThe hydrogen permeability of 99.98% pure nickel pre-irradiated by the light ions of He, O, N, or C was studied as well as the hydrogen permeability of the same material under simultaneous bombardment by the same light ions and hydrogen ions. The experiments were carried out in the 100–300°C temperature range. The energy of these light ions used for irradiation was 30 keV, while the irradiation doses varied from 1×1021 m−2 to 1×1023 m−2. It was found that both of these types of irradiation caused the hydrogen permeability of the studied materials to decrease. The extent of decrease in hydrogen permeability was higher in the case of simultaneous bombardment of a sample with the hydrogen ions and ions of one of the light elements mentioned above. Investigations on the hydrogen permeability of nickel and type 16–15 stainless steel with certain structural features under hydrogen ion bombardment were also carried out. The influence of preliminary cold working (5, 15, 30, and 50%) on the hydrogen penetration as well as the effect of the grain size on the hydrogen permeability of these materials were also investigated. The grain size of the samples was in the 3–5, 30–50, and 400–600 μm ranges. The experiments were carried out at 150 and 200°C. It was found that preliminary cold working of the studied materials, as a rule, increased their hydrogen permeability. The investigation of the effect of grain size on the degree of hydrogen penetration through the steel showed that it was practically the same for the large-grain and medium-grain steel. The hydrogen permeability of the small-grain steel was about twice as that of the large- and medium-grain steel. Investigations on the hydrogen permeability (HP) through structural materials under simulation of thermonuclear reactor (TR) working conditions are very important in connection with solving the material science problems of controlled thermonuclear fusion (CTF).