Tritium detection in plasma facing component by imaging plate technique

Tritium imaging plate technique (TIPT) has been successfully applied to measure the tritium areal distribution on various graphite tiles used as limiters in TEXTOR. It is observed that tritium distribution on the ALT-II tile is quite homogeneous and different from deuterium distribution and the tritium in redeposited layer is rather small. Such tritium distribution on the graphite tiles in TEXTOR behaves different compared to those in JET and TFTR where tritium was used as fueling gas or NBI injection. In JET and TFTR the tritium is part of the fuel and is co-deposited and retained in a similar manner as the deuterium. In a device like TEXTOR, the high-energy tritons are decoupled from the thermalized deuterons and show different behavior of retention; the main retention mechanism is deep implantation rather than co-deposition with eroded carbon on redeposition-dominated areas. It is also found that the tritium distribution measurements give useful new information on plasma-wall interactions.