Unsolved issues on tritium mass transfer in Li–Pb liquid blankets

In order to estimate mass-transfer properties of tritium (T) in Li + Pb binary alloys as a blanket material for fusion reactors, variations of the H solubility with different Li and Pb compositions are presented. Deviation of the Li + Pb binary liquid mixture from an ideal solution model is discussed, and a correlation is proposed for predicting properties of various Li + Pb alloys. Isotope effects on solubility and diffusivity of Li17Pb83 between H and D are correlated based on an isotropic harmonic oscillation model. The zero-point energy of H atoms dissolved in Li17Pb83 is determined from the comparison with the model. Wettability at the interface between liquid Li17Pb83 and metallic walls and effects of impurities on H solubility are discussed.