Surface effects on plasma-driven tritium permeation through metals

The model for the plasma-driven tritium permeation proposed by Doyle and Brice [J. Vac. Sci. Technol. A 5 (4) (1987) 2311] and by Waelbroeck et al. [Forschungazentrum, Julich, Germany, Jul-1996, 1984] has been developed. An improved analytical expression for the plasma-driven tritium permeation in the steady state is presented. Using the presented analytical expression, the influence of surface conditions on the front and the back sides of a metal has been considered for the plasma-driven permeation of tritium through both endothermic and exothermic metals. The presented pictures allow us to define the steady-state tritium permeation in a wide range of the surface conditions: as for an absolutely clean surface and a bare (presence of small amounts of impurities) surface as for contaminated with different impurities surface. This result can be useful for choosing the plasma-facing material for the future steady-state fusion device.