It is required to develop an efficient tritium fueling cycle keeping the overall tritium breeding ratio larger than 1.0 and a reliable tritium confinement system assuring the radiation safety of tritium in construction of the D-T fusion reactor. The blanket is the place where the tritium recovery system has contact with the cooling system for electricity generation at the elevated temperature. Therefore, design of efficient means to recover bred tritium with minimum permeation loss is to be made.

It is proposed in this study to construct a recovery system using the Pd alloy with adsorption bed after a precious metal catalyst bed. Effects of existence of water on dissociation reaction of hydrogen on palladium alloy membrane and on recombination reaction are discussed in this study for the case when 800 Pa of water vapor is introduced to the permeation primary side and/or permeation secondary side for the case when water vapor co-existed, and it was observed that water vapor prevents hydrogen permeation through palladium alloy at the lower temperature than 473K.