Mechanical Reliability of Oxidized Zircaloy-4 Alloy Nuclear Cladding Tube in Compression

Abstract

Ring compression tests on the oxidized Zircaloy-4 cladding tubes were performed to examine the mechanical reliability of Zircaloy-4 cladding tubes. In compression of the non-oxidized cladding tubes, large load drop associated with the cladding failure appeared at the total displacement of 6.3 mm. After oxidation at 600°C for 24 hrs and 700°C for 3 hrs, small drop of load resulting from small cracks in the thin oxide film was observed at the total displacement of 1.0 mm. After oxidation at 700°C for 24hrs, load was extremely low, but catastrophic fracture occurred at the total displacement of 2.4~2.8 mm. The oxide of Zircaloy-4 cladding tubes formed at high temperature apparently causes the premature failure of tubes.