In-Situ Neutron Diffraction Study of Zircaloy-4 Subjected to Biaxial Tension

Abstract

Zircaloy-4 is widely used as fuel element cladding in nuclear reactors. Pellet-Clad Interaction (PCI) failure is a concern for many water reactor fuel designs. Extensive work on the mechanism of PCI failure has led to the conclusion that Stress Corrosion Cracking (SCC) induced by iodine vapour in the temperature range relevant to fuel operation is the most probable cause of PCI failure in zirconium alloy fuel element cladding. In-situ neutron diffraction measurements performed on tubular Zircaloy-4 specimens simultaneously pulled in tension and pressurized internally provide information on the effects of stress biaxiality on the distribution of stresses at the crystal level during loading.