Mathematical Description of Measuring Results of the Tritium and Hydrogen Permeation Through Surface Oxidized Alloys

Steady state as well as transient hydrogen permeation models have been calculated. Especially a complex pressure dependence for bright as well as oxidized alloys could be derived and compared with the various experimental findings confirming the observed transitions between square root and linear pressure dependence in the different pressure ranges. A diffusion limited transport model with linear boundary conditions has been used to describe time dependent permeation. Thereby the oxide has been treated as a heterogeneous two phase system, where the “good” phase mainly determines its effectiveness in permeation reduction which is more or less lessened by the “bad” phase.