ADSORPTION CHARACTERISTICS OF WATER-VAPOR ON LI2ZRO3

Lithium metazirconate (Li2ZrO3) is one of the probable candidates for the tritium breeding material because of its potential to give a fair tritium breeding ratio, stability at high temperature and stability in atmosphere containing water vapor. Investigation of the adsorption performances of water vapor on Li2ZrO3 is important for optimization of the way to recover bred tritium from Li2ZrO3, for estimation of tritium inventory in the breeding blanket and for quantification of the hydrogen isotope exchange reaction. The amount of water vapor captured on Li2ZrO3 was studied in the temperature range of 393-1073 K using the breakthrough method, and adsorption isobars and isotherms of water vapor on Li2ZrO3 were proposed based on the data obtained. The water capture phenomenon was attributed to the dissociative adsorption, and the apparent heat of adsorption was determined to be 10.7 kJ/mol. The tritium inventory due to sorption for Li2ZrO3 was compared with those for Li2O, LiAlO2 and Li4SiO4. Furthermore, the tritium inventory in the blanket due to sorption was compared with that due to diffusion in the crystal grain.