Several environmental impact analyses have identified gaseous permeation from blanket regions, through metals and into the steam cycle, as the major pathway for routine tritium emissions from fusion power plants. The propensity of gases and molten salts to impede tritium permeation have been examined, and the results indicate that helium as a coolant or flibe (LiBeF3) as a blanket material would reduce tritium permeation in extant 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 that calculated under the assumption (used in the design report) that fluids would not affect the permeation rate. The tritium permeation characteristics of novel reactor designs may be evaluated by a straightforward procedure. First, the tritium mass transport rates in the fluids are computed from the Chilton-Colburn j-factor analogies, the Gilliland correlations, or a simple transformation of heat transfer data. The asymptotic fluid-limited and metal-limited permeation rates are then equated to identify the tritium pressure regime in which a transition occurs in the rate-limiting mechanism.