Performance of irradiated copper and zirconium barrier-modified Zircaloy cladding under simulated pellet-cladding interaction conditions

Expanding mandrel laboratory simulations of the pellet-clad interaction (PCI) mechanism (including argon, iodine, and cadmium environments) were employed to evaluate copper barriers and zirconium-lined tubing performance. Zircaloy-2 and copper-plated and zirconium-lined barrier tube specimens were tested in the unirradiated (cold-worked) and in the irradiated (recrystallized) conditions at about 600 K. Tubing was irradiated at 620 K to a fast (E>1 MeV) fluence near 2*10$sup 25$ n/m$sup 2$. Brittle PCI-type failures were produced in unirradiated Zircaloy-2 tubing by expanding mandrel loading with iodine and cadmium. Failure strains were further reduced for irradiated Zircaloy-2 tested in each embrittling environment. Fractographic analyses revealed brittle fracture surface features similar to those reported for failed fuel rods. 15 refs