DEVELOPMENT AND VALIDATION OF A NEW EXPERIMENTAL DEVICE FOR STUDIES OF IODINE STRESS CORROSION CRACKING OF ZIRCONIUM ALLOYS

摘要

Zirconium alloys are widely used in the nuclearindustry as cladding material due to their goodthermo-mechanical, chemical and neutronicproperties as well as an excellent general corrosionresistance in many environments. Nonetheless,Iodine-induced Stress Corrosion Cracking (ISCC)is an identified failure mechanism that can occurin nuclear fuel cladding as a result of PelletCladding Interaction (PCI) during incidental powertransients in the reactor. In this study a newexperimental device allowing studies of ISCCin a controlled chemical environment is presented.The experiments are performed in an environmentthat is free of contaminants. First results show thatthe time to rupture of the specimen is inverselyrelated to the iodine partial pressure. The lowesttested iodine partial pressure, 150 Pa, resultedin an ISCC crack. Post-Mortem microstructuralobservations provide evidence of iodine corrosionof Zircaloy-4.