Influence of Zirconium Alloy Strength on SCC Susceptibility of Cladding Tubes

Iodine-induced stress corrosion cracking (SCC) of zirconium cladding tubes is a well known problem of fuel cladding exploitation in nuclear reactor core. In the present work we have applied a previously developed approach of SCC-testing of zirconium cladding tubes which includes acoustic emission measurements, fractography and metallography analysis to study how the zirconium alloy strength influence the mechanisms, kinetics and overall resistance of cladding tubes to iodine-induced SCC. A set of different alloy claddings having different strength (yield strength and ultimate strength) have been comparatively tested for SCC. Claddings have been manufactured from different industrial zirconium alloys and have been tested in as-received conditions. It have been shown, that zirconium alloy strength increases susceptibility of claddings to SCC via changing mechanisms and kinetics of SCC.