Corrosion of Zircaloy-4, Zr-1Nb and FeCrAl alloys in deaerated water at 330 °C and 14 MPa: Superior corrosion resistance and corrosion mechanism of FeCrAl alloy by experiments and molecular dynamics simulations

After the Fukushima explosion, the research and development of accident tolerant fuel (ATF) cladding has become a hot spot in the nuclear field. In this work, corrosion behavior of Zircaloy-4, Zr-1Nb and FeCrAl alloys was investigated in deaerated water at 330 °C and 14 MPa. All alloys were found to lose weight. In Li/B water, the corrosion resistance followed an order of FeCrAl > Zr-1Nb > Zircaloy-4. Local corrosion occurred on the Zircaloy-4 surface and developed towards the interior of the matrix, leading to selective oxidation. A certain thickness of oxide layer was formed on the surface of Zr-1Nb, but the distribution was uneven. Significant oxide exfoliation made Zr-1Nb display complex defects. The oxide film of FeCrAl alloy had a double-spinel structure. Low surface adsorption energy and weak interaction between Fe and O atoms is responsible for superior corrosion resistance of FeCrAl alloy.