The Impurity Processing System for the JET Active Gas Handling System — Inactive Commissioning

The Impurity Processing (IP) system is designed to recover tritium from tritiated compounds (Q₂O, C_xQ_y, NQ₃, with Q = H, D, T and x>=1, y>=4) collected from the JET torus or generated during the processing of gases inside the Active Gas Handling System (AGHS). The recovery process involves dilution of the impurities in helium, addition of oxygen, recirculation of the helium-impurities-oxygen mixture over a hot recombiner (773K) to generate water and CO₂, and trapping of the water on 160K cold surfaces. The remaining gas species He, CO₂, O₂, N₂ (with a very small tritium concentration) are transferred finally to the Exhaust Detritiation (ED) system for further reduction of the tritium concentration by at least a factor of 1000. The cold trap is heated (473K) and the water vapour passed over two hot iron beds at 823K to “crack” the water. The recovered hydrogen isotopes are stored in cold uranium beds (U-beds) for further processing in AGHS.