Ex-situ characterization of pre- and post-transient specimens of Zr1Nb alloys

The ex-situ tests were performed with Zr1Nb alloy specimens that had been pre-exposed to the environment with an elevated concentration of lithium (70 ppm Li as LiOH) at the temperature of 360 °C for a period of 63 to 77 days prior to the measurement. The impedance changes at the phase alloy- -oxide-electrolyte interface were monitored using the ex-situ electrochemical impedance spectroscopy. At the same time, the progress of electrolyte penetration in the oxide porous structure was studied. The oxidic layer and the electrolyte penetration are characterized by the elements of the equivalent circuit model and Jonscher analysis that enables calculation of the dielectric thickness of the oxide.