The mechanism and kinetics of the fuel cladding failure during loading after high-temperature oxidation

•Mechanism of fuel cladding failure during loading after high-temperature oxidation was studied.•The fracture of the samples starts with the formation of brittle cracks 30–50μm long in α-layer.•The sample based on Zr-electrolytic has lower plasticity compared the sample based on Zr-sponge. Complex analysis of the acoustic emission (AE), load–strain diagrams and step-by-step metallographic analysis have been used to examine the sequence of damage accumulation under loading in tubular E110 zirconium alloy specimens, which were subjected to high-temperature oxidation (T=1100°C, ECR=10%). The ECR value was determined by weight gain measurements. The fracture of samples under loading begins with the formation of brittle microcracks 30–50μm long in the α-layer. Further, the cracks propagate simultaneously into oxide and “prior β”-layer until the formation of a through-wall crack.