A study of the breakaway oxidation behavior of zirconium cladding materials

In order to investigate breakaway oxidation behavior, the high temperature oxidation test using zirconium claddings was performed at the temperature of 1000 °C for up to 5000 s in a steam environment. After the high temperature oxidation test, SEM microstructural observation and high temperature XRD analysis were applied to evaluate the oxide characteristics with alloy composition and oxidation time. From the systematic analysis of the oxide and matrix, it could be interpreted that the breakaway oxidation behavior was influenced by the hydrogen concentration at the oxide and metal interface rather than oxide phase transformation between the tetragonal phase and monoclinic phase. The hydrogen effect near the oxide metal interface was affected by the metal morphologies between the oxygen stabilized alpha phase and prior-β phase.