In-reactor oxidation of zircaloy-4 under low water vapor pressures

•Observed oxidation of Zircaloy-4 under low water vapor pressure.•Detailed description of in-reactor test assembly.•Oxidation and hydrogen absorption measurements provided.•Comparison between in- and ex-reactor results. Complementary in- and ex-reactor oxidation tests have been performed to evaluate the oxidation and hydrogen absorption performance of Zircaloy-4 (Zr-4) under relatively low partial pressures (300 and 1000Pa) of water vapor at specified test temperatures (330 and 370°C). Data from these tests will be used to support the fabrication of components intended for isotope-producing targets and provide information regarding the temperature and pressure dependence of oxidation and hydrogen absorption of Zr-4 over the specified range of test conditions. Comparisons between in- and ex-reactor test results were performed to evaluate the influence of irradiation.