Isotopic exchange between hydrogen and deuterium in the process of permeating through Li0.17Pb0.83

The permeation process of hydrogen isotopes through Li0.17Pb0.83 has been investigated experimentally. We obtained the overall D permeation rates that take into consideration of the effects of the H–D isotopic exchange reaction on the surface and diffusion in the Li–Pb layer. It was proved that the rate-determining step was not the surface reaction but the diffusion in the Li–Pb bulk. We proposed a system of gas–liquid counter-current extraction using a packed column for continuous tritium recovery. The concentration profiles through the column and tritium extraction rates are calculated. It is estimated that the column height of 5 m is sufficient to achieve the tritium recovery ratio of 99.999%. This counter-current extraction method is easy to operate and efficient to recover tritium from Li–Pb.