Gas recovery system for the first JET tritium experiment

Abstract

Abstract Gas recovery during the first JET tritium experiment was mainly based on the use of a cryopump designed earlier [1] for collection of torus exhaust gas. This cryopump system was extended to include collection of gas from the neutral injectors and to provide sampling and diagnostic facilities such as an ionisation chamber for on-line tritium accounting, a mass spectrometer for gas analysis and a sampling manifold for off-site tritium accounting. The cryopump was backed by a collection system comprising a reservoir, recirculation pump and 4 uranium beds originally designed for the JET Active Gas Handling System [2]. During operation of the system from start of the experiment on 04.11.91 until 20.12.91 a total of 1450 bar 1 of gas with a total tritium content of 4.3 × 10 13 Bq (1162 Curies) were collected. A small exhaust detritiation system was installed to reduce emissions in case of accidents such as major torus or neutral injector air or water leaks. As no major problems were encountered during the experiment, it was not used.