Surface inventory of tritium on Li2TiO3

Though lithium ceramic materials such as Li2O, LiAlO2, Li2ZrO3, Li4SiO4 and Li2TiO3 are considered as breeding materials in the blanket of a D-T fusion reactor, the release behavior of the bred tritium in these solid breeder materials has not been fully understood, yet. It has been pointed out by the present authors that it is essential to understand such mass transfer steps as diffusion of tritium in the grain of breeder material, absorption of water vapor into bulk of the grain, and adsorption of water on surface of the grain, together with two types of isotope exchange reactions for estimation of the tritium inventory in a uniform solid breeder blanket under the steady-state condition. The adsorption capacity and the isotope exchange capacity on the Li2TiO3 surface are experimentally obtained in this study. Comparison of the tritium inventory estimated for the Li2TiO3 blanket with the inventory for LiAlO2, Li2ZrO3 or Li4SiO4 blanket using the model presented by the present authors shows that the Li2TiO3 blanket gives the smallest tritium inventory among the candidate ceramic breeding materials.