Tritium tests with a technical PERMCAT for final clean-up of ITER exhaust gases

One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10−5 g h−1 into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 108 is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 105 for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination factors and clearly demonstrated that the required overall ITER decontamination factor can be reached with a technical PERMCAT as the final clean-up step of the CAPER process.