Out-of-pile and in-pile perfomance of advanded zirconium alloys (HANA) for high burn-up fuel

The performance of the advanced Zr alloys (HANA) for a high burn-up fuel has been evaluated in the out-of-pile and in-pile conditions. The corrosion resistance of the HANA claddings was superior to Zicaloy-4 in a PWR-simulating loop condition. The improved corrosion resistance of the HANA claddings was attributed to the fine distribution of the precipitate. HANA claddings showed a higher creep resistance as compared to Zircaloy-4 from the thermal creep test. The deformation behavior of HANA in a LOCA condition was similar to Zircaloy-4. Threshold ECR value of HANA was higher than the conventional value of 17% in Zircaloy-4, which is mainly due to the fact that the Nb decreases the oxidation rate as well as the hydrogen pickup. Fretting wear test revealed that HANA claddings have a similar wear resistance to Zircaloy-4. From the irradiation test up to burn-up of about 12 GWd/MtU, HANA claddings showed a better corrosion resistance as well as a better creep resistance than Zircaloy-4. The in-pile corrosion resistance of the HANA claddings was improved by 40-50% as compared to Zircaloy-4 on the basis of the oxide thickness measurements.