Possible techniques for the detritiation of first wall materials from fusion machines

Tritium in first wall materials of fusion machines is a matter of concern not only for inventory purposes but also for safety reasons. In the first wall carbon tiles, tritium is found predominantly in a very thin codeposited layer and/or implanted in the surface layers. Since the tiles must eventually be disposed off in a repository it is desirable to reduce the total tritium inventory in the tiles down to the corresponding low level waste category. In this context, the development of detritiation techniques for graphite and CFC tiles removed from the first wall of fusion machines is of paramount importance. However, the experimental techniques investigated until now are limited by the conditions and techniques permissible inside the torus. Nevertheless, for tiles removed from the reactor more severe treatment techniques are acceptable. Working in that direction, numerous screening tests have been carried out at the Tritium Laboratory in Karlsruhe (TLK).