Recovery system using adsorption bed-catalyst bed arrangement for tritium in room air

At present, the tritium recovery system with a heated precious metal catalytic oxidation bed followed by a cooled adsorption bed is used to recover tritium when it is released into the room air of tritium handling facilities. But this arrangement of the tritium recovery system has such disadvantage as to require a large capacity of adsorption bed because a large amount of water vapor in the room air has to be recovered with the released tritium. The tritium recovery efficiency with this arrangement decreases when trouble occurs with heating device of the catalyst bed or cooling device of the adsorption bed. The tritium recovery system constituted by a pre-adsorption bed with no cooling device followed by a precious metal catalytic oxidation bed with no heating device is proposed in this paper. In this new arrangement, the tritium recovery activity of the precious metal catalytic oxidation bed is maintained because water vapor is taken away from the process gas in the pre-adsorption bed to such a degree as that catalytic oxidation is not hindered, and tritium is captured to hydrophilic substrate of the precious metal catalyst with the higher T/H ratio than that in the inlet gas stream through adsorption and isotope exchange reaction after oxidation in the proposed recovery system. (author)