Assessment of the heating technique as a possible ex situ detritiation method for carbon wall materials from fusion machines

Detritiation by heat treatment of graphite or carbon fibre composite (CFC) tiles retrieved from the Tokamak Fusion Test Reactor (TFTR) was assessed using the standard and well proved technique of full combustion combined with liquid scintillation analysis. Complete carbon tiles were heated in a oven to 500 °C in air for one hour at Princeton Plasma Physics Laboratory (PPPL) and sent to Tritium Laboratory Karlsruhe (TLK) for surface and depth profile analysis. Coring/full combustion technique performed on the treated and untreated tiles, both graphite and CFC, has shown that only the tritium held close to the surface (few tens μm) is efficiently released by baking in air while the bulk tritium is almost unaffected. Therefore, baking the tile under air, even at 500 °C, does not detritiate the bulk.