During the Deuterium-Tritium-Experiment (DTE1) the JET Active Gas Handling System (AGHS) supplied tritium and deuterium to the JET tokamak and processed the exhaust gases of the torus with the main intention to recycle tritium and deuterium, to detritiate impurities containing tritium and to discharge detritiated gas mixtures via the stack.The gas processing in the AGHS was performed in various subsystems which were partially discussed previously /1, 2/. Two important subsystems were the preparative Gas Chromatographic (GC) system /3/ and the Cryogenic Distillation (CD) system /4, 5/ which were used for hydrogen isotope separation and enrichment of deuterium and tritium. This paper will present the use and performance of both systems during DTE1 and the subsequent clean-up phase until the start of the Remote Tile Exchange (RTE) at JET. It will be shown that the operation of both systems was fundamental for the successful re-processing of the gases in AGHS and the supply of pure tritium and deuterium. The preparative GC system built for 100% enrichment of large amounts of T2 and D2 must be distinguished from the analytical GC (AN-GC) system /6/ which is used for quantitative determination of gas contents in various gas mixtures.