Behavior of Tritium Permeation Induced by Water Corrosion of Alpha Iron Around Room Temperature

In order to understand behaviors of hydrogen uptake and permeation in pure (αiron (αFe) during water corrosion around room temperature, hydrogen permeation experiments for a αFe membrane have been conducted by means of tritium tracer techniques. Hydrogen produced by water corrosion of αFe is trapped and/or blocked in/by product oxide layers to delay hydrogen uptake in αFe for a moment. However, the oxide layers do not work as a sufficient barrier for hydrogen uptake. Some of hydrogen dissolved in αFe could normally diffuse and permeate through the αFe bulk. Assuming hydrogen dissolution at the water/Fe interface proportional to the square root of the hydrogen pressure (Sieverts’ law), the partial hydrogen pressure were estimated to be 0.7, 5.0 and 9.5 kPa at 303, 323 and 348 K, respectively.