Kinetics of hydrogen desorption from the first wall of a thermonuclear reactor

Abstract

A simple model is proposed for the description of hydrogen desorption from a TNR first wall in steady conditions, taking account of radiationally stimulated desorption. An expression is obtained for the degree of cover of the surface. It is shown that, in TNR conditions, the main contribution to the desorbed flux is from the recombinational term, Radiationally stimulated desorption leads to a slight correction. The dependence of the desorbed flux on the hydrogen flux close to the surface is investigated. In a series of cases which are of practical importance, the general Eq. (7) may be simplified. As well as a quadratic concentration dependence of the thermodesorbed flux, a linear dependence is also possible. Equations (13) and (14) may be used in calculating the hydrogen permeability and tritium accumulation in the TNR first wall.