Steady state hydrogen transport in solids

Abstract

The analytical formalism for evaluating the steady state hydrogen (tritium) inventory, recycle and permeation rate and recycle time for surfaces exposed to the plasma of an operating magnetic confinement fusion reactor is reviewed and new material relevant to the application of this theory is presented. The formalism includes hydrogen trapping, diffusion, and effects of thermal gradients (e.g., Ludwig-Soret effect), and is applicable for all orders of release kinetics at the inner and outer surfaces. The problem is formulated in terms of a unitless transport parameter, W=(Rφ/D)(k₁/φ)^l/r, where r is the order of the release kinetics, R is the range of the implant, φ is the penetrating part of the incident flux, kl is the recombination coefficient and D is the diffusion coefficient. The steady state analytical theory is applied to several materials of interest to controlled fusion.