LONG-TERM PERMEATOR EXPERIMENT PETRA AT THE TRITIUM-LABORATORY-KARLSRUHE - COMMISSIONING TESTS WITH TRITIUM

During commissioning of the PETRA facility all components were tested singly and sequentially using hydrogen isotopes (incl, up to 1.3 g tritium as DT) and relevant impurities. The operation of the facility in conjunction with the required infrastructure systems of the Tritium Laboratory Karlsruhe (TLK) was also demonstrated. To characterize the PETRA PdAg permeator hydrogen break-through curves for H-2, Da and DT as well as He break-through curves for various H-2/D-2/He gas mixtures were determined at 300 and 400 degrees C. A suitable method was developed to verify the mechanical integrity of the permeator during runs with tritium. The H-2 and D-2 permeation losses into the isolation vacuum of the permeator were quantified and compared with model calculations. Hydrogen permeation into the isolation vacuum could be kept at levels low enough to permit an undisturbed continuous operation of the permeator using a ZrCo tritium storage vessel. All pumps and pump combinations were examined with respect to the achievable vacua and compression ratios employing relevant gases and their mixtures. Loop-integrated infrared analysis of high signal and background stability is used to verify the integrity of the permeator and to study the possible occurrence of radiochemical reactions in the gas phase. It was shown that the ZrCo tritium storage vessel of the PETRA facility can be employed avantageously for the handling of tritium when used in combination with a Normetex scroll pump (18 m(3)/h)/Siemens metal bellows double stage compressor pump sequence. With this combination it is possible to extract at < 320 degrees C > 98% of the hydrogen isotopes from the ZrCo storage vessel with a) negligible permeation losses, b) without the danger of disproportionation of the intermetallic compound and c) with minimization of the tritium inventory in the facility.