Effect of molybdenum on electron radiation damage of Zr-base alloys

The effect of Mo on the radiation damage of the Zr–1Nb–1Sn–0.1Fe alloy was studied by in situ electron beam irradiation using a high-voltage electron microscope (HVEM) operated at 1 MeV equipped with a heating device. Regardless of the Mo content, the nucleation rate as well as the growth rate of radiation defects increased with irradiation temperature. Addition of 0.5% Mo decreased the initial nucleation rate and suppressed the growth rate of radiation defects in the alloy at 300°C. Extended annealing heat treatment at 650°C further increased the radiation resistance of the Mo-containing alloy.