Compatibility of zirconium alloy with high temperature sodium

Furukawa, Tomohiro  ; Kato, Shoichi ; Maeda, Shigetaka   

Application of zirconium alloy as a neutron reflector around the driver fuel region of the Japanese experimental fast reactor JOYO has been planned for a further increase of core average burn-up. In this study, corrosion tests on the zirconium alloy bar were performed for 1000 h at 650 C and 500 C in stagnant sodium whose initial dissolved oxygen was 1 ppm. Weight gain caused by high temperature oxidation in sodium was slightly observed on the specimens. The microstructure of the specimens was the same as that of as-received specimen. No dissolution of alloy elements such as Zr, Sn, Cr and Fe into sodium was observed. Ultimate tensile strength of the exposed specimens was the same as that of as-received specimen. In fact, no effect of sodium exposure on mechanical strength was observed.