Tritium inventory in the first wall of JET

At the start of the shutdown following the DTE1 experiment at JET there rem ained 6.2 g of tritium in the JET vacuum vessel. An attempt has been made t o establish the location of this tritium by measuring components taken from the vessel. A total of 2.0 g of tritium was recovered by out-gassing and 1 .5 g was originally estimated for the flakes/deposits from measurement of c ollected flakes. Measurements on tiles removed from the vessel indicate tha t all the vessel tiles contain less tritium than expected at similar to0.1 g. Some uncertainty exists about the location of the remaining tritium. Fur ther investigation has shown that a significant quantity of flakes (more th an originally estimated) exists in the sub divertor region. It is believed that the missing tritium is present in the flakes in the sub divertor regio n. However, until this material can be collected and quantified other possi ble sources cannot be excluded. The reasons for the formation of the flakes /deposits are discussed. (C) 2000 Elsevier Science B.V. All rights reserved .