Assessment of the performance of the JET exhaust detritiation system

The exhaust detritiation system (EDS) is one of the key safety related syst ems, which allows operation of the Joint European Torus (JET) machine. Its role is to detritiate the exhaust gases in case of an accident and to minim ise the tritium release to the environment. EDS has also been used on JET d uring the last 3 years for maintenance purposes. During the main phase of t he deuterium-tritium experiment (DTE1), the EDS was the final stage for det ritiation of gases coming from the Torus vessel. There is a regulatory requ irement to prepare an 'Engineering Substantation' of key safety related sys tems. Although this requirement applies to EDS when dealing with accidental tritium releases, it has been possible to investigate the efficiency of th e system by analysing the experimental data obtained during maintenance. In 2000, during the shutdown, campaign measurements on EDS have been performe d to determine its efficiency on a daily basis. Detritiation factors (DF) r ange between 20 and 80 000. Results are presented and discussed in relation to the requirements of the JET safety case and the factors, which cause ap parent low DFs. An enhancement of the system for tritium control tracking i s proposed. (C) 2001 Elsevier Science B.V. All rights reserved.