Tritium Management in an All-Carbon First Wall Tokamak Reactor

The erosion of wall materials is an inevitable consequence of plasma-particle and charge-exchange neutral interactions with the wall armor in tokamak fusion reactors. The subsequent redeposition of eroded atoms, and the inclusion of hydrogen isotopes in such deposits, will lead to an in-vessel inventory of tritium, temporarily removing this tritium from the fuel cycle. The magnitude of the deposition rate will be sufficiently large that ongoing procedures for controlling the deposit thickness, and the tritium content, will be required. For carbon walls, it is possible to remove such deposits in situ through oxidation, converting the carbon to CO or CO2. Any tritium released will be in the form of tritiated water (DTO, T2O) which will require special processing in the reactor tritium plant. The technology for processing high-tritium content water using steam electrolysis systems based on solid oxide electrolyzers is largely available and is described in this paper.