Hydrogen Permeation Behavior Through F82H at High Temperature

F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 °C because it is considered that F82H can be used up to 30,000 hours at 550 °C. However, it is necessary to assume the situation where F82H is heated over 550 °C in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 °C to 800 °C. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 °C to 700 °C agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed.  After the hydrogen permeation reached in a steady state at 700 °C, the F82H sample was heated to 800 °C. The permeability of hydrogen through F82H sample which was once heated up to 800 °C was lower than that of the original one.