Isotopic exchange between hydrogen and deuterium in the process of permeating through Li_0.17Pb_0.83

The permeation process of hydrogen isotopes through Li _0.17Pb_0.83 has been investigated experimentally. We obtained the overall D permeation rates that take into consideration of the effects of the H-D isotopic exchange reactionon the surface and diffusion inthe 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 of5m 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.