Kinetics of Tritium Recovery from Liquid Lithium by Molten Salt Extraction

The rate of tritium recovery from liquid lithium by molten salt extraction was measured. The mass balance of tritium was always good during extraction and the overall mass transfer coefficient was evaluated. The dependences of the mass transfer coefficient on salt and temperature are explained by considering the predominant resistence to the mass transfer in the salt phase. The semi-empirical equation is given by K_M* (cm/s) = 2.2×10⁻⁴(T(K)/µ_salt (cp))^1/2 where µ_salt is the viscosity of salt.

The reference scheme of molten salt extraction is re-evaluated with the newly obtained data. Not only from the thermodynamic but also from the kinetic points of view, it is shown that a design goal of the tritium concentration of 1 wppm in lithium would be reached by combining a reasonable number of extractor units. A mixer-settler with mechanical stirrer may be sufficient for the extractor.