Effect of helium additions in plasma on hydrogen penetration from plasma discharge through Kh16N15M3B steel

The coefficients of hydrogen diffusion for Kh15N16M3B steel in the temperature range 250 ... 700 deg C and the diffusion activation energy were determined on the plasma facility ''Drakon'' (reflex discharge). The diffusion coefficients in this temperature range are in good agreement with the published data on such steels. The effect of helium additions in hydrogen plasma on hydrogen penetration through the Kh15N16M3B steel at 275 deg C was studied. It is shown that the 50% helium addition (in volume) in hydrogen plasma or the irradiation of this steel with pure helium plasma decrease its hydrogen permeability by 8 and 5 times. The results obtained can be used to solve the problems of controlled thermonuclear fusion, since the Kh15N16M3B steel is a probable structural material for fusion reactors. 8 refs., 6 figs