Deuterium permeation through the low-activated V-4Cr-4Ti alloy under plasma irradiation

Vanadium-based alloys are considered as candidate structural materials for nuclear fusion and fast nuclear reactors. Some properties of vanadium alloys are especially advantageous for nuclear fusion facilities, namely, a fast decay of induced activity, resistance to liquid lithium media and high-temperature strength. At the same time, V-alloys absorb and dissolve hydrogen isotopes in large quantities, and the mobility of dissolved hydrogen is high even at cryogenic temperatures. Thus, vanadium and its alloys, as some other metals of the fifth group (Nb, Ta), are characterized by high hydrogen permeability. This allows their usage as membranes for the diffusive purification of hydrogen isotopes. Under plasma irradiation of an inlet surface of such membranes, suprathermal hydrogen atoms and ions with quite high possibility penetrate through the adsorption barrier and diffusing inside materials bulk can reach an outlet surface. This paper aims to study the plasma-driven permeation (PDP) of deuterium through V-4Cr-4Ti alloy. It was shown that the permeation probability of deuterium under plasma irradiation for V-4Cr-4Ti alloy varies in a range of chi = 0.03 divided by 0.12 for T = 600 divided by 800 K, which leaves open the possibility of such alloys usage for hydrogen isotopes purification in the fusion reactor exhaust.