Ultra Low Tin Quaternary Alloys PWR Performance—Impact of Tin Content on Corrosion Resistance, Irradiation Growth, and Mechanical Properties

The performance of Zr1NbSnFe alloys within the range of Sn 0–0.65 % and Fe 0.03–0.35 % were studied through irradiation of fuel rods in two pressurized water reactors (PWRs) operating with significantly different fuel management strategies. Material test rod irradiations have also been launched in order to determine irradiation growth and corrosion behaviour on tubes irradiated under conditions representative of guide tubes. Results show that the increase in tin content up to 0.3 % does not significantly change the corrosion resistance nor the hydrogen pick-up compared to Zr1Nb alloy, while ensuring a higher creep resistance and an improved dimensional stability. On the contrary, at 0.5 % Sn, the corrosion resistance can be significantly degraded under demanding conditions. The iron addition to the alloy can be considered as a second order parameter for both corrosion and creep properties.