Computer code PERI - permeation of hydrogen through metal membranes, release from metal surfaces and inventory in metal walls

The computer program PERI was developed as an aid to interpret experimental observations in connection with the permeation of hydrogen through metal membranes and the release of hydrogen from metal walls (Langmuir effect). Such experiments are made to find out the materials constants determining the diffusion of hydrogen as well as its solubility and release from the material. Their knowledge is indispensable for the operation of fusion plants and permits to calculate the hydrogen recycling, the inventory in the wall and the permeation (e.g. of tritium). Experiments have shown that the permeation flow density at low primary pressures (< or approx. 1 Torr) can become directly proportional to the latter and not - as Richardson's equation would lead one to expect - to the square root of the pressure. The validity of Richardson's equation, however, is frequently taken for granted when materials constants are determined. (orig./GG)