Limitations on hydrogenic gas transport at ultra-low pressures

This study examines the propensity of gases and molten salts to impede tritium permeation. The results indicate that helium as a coolant or flibe (LiBeF3) as a blanket material would reduce tritium permeation in extant reactor designs to negligible rates. For example, the tritium release rates from the Princeton Reference Design would be two to three orders of magnitude less than those calculated under the assumption (used in the design report) that the fluids do not effect the permeation rate. A straightforward procedure is proposed for evaluating the tritium permeation characteristics of novel reactor designs. The role of surface phenomena at ultra low pressures has been examined experimentally