Reducing Hydrogen Penetration through Corrosion Layer Formed on Zirconium Alloys by Iron Addition

Latest post-irradiation experiment results of Zry-2 and HiFi alloy (0.4%Fe-Zry2) showed that iron addition reduces the hydrogen pickup by these alloys compared to oxidation amount. In order to clarify the mechanism of reduced hydrogen absorption rate, (1) autoclave test, (2) surface potential measurement and (3) hydrogen absorption test of the intermetallic compound were carried out. Based on these results, a tentative mechanism for hydrogen absorption by zirconium alloys is proposed, taking into account of both the electrical potential gradient over the oxide film as well as the SPP window for hydrogen absorption.