Methodology for mechanical property testing of fuel cladding using an expanding plug wedge test

An analysis is presented to determine the stress–strain response of ring-shaped test specimen subjected to internal pressurization using a radially expanding plug. Previous work has been reviewed using this test method to determine the residual ductility of irradiated nuclear fuel cladding and highlight the role of several parameters on the distribution of stresses and the mode of failure. It is shown that bulging effect, which had previously not been accounted for, has a significant effect on the distribution of stresses and mode of failure. The new analysis provides guidelines for optimizing specimen geometry and loading conditions and a means for determining the hoop stress σθ in the ring-shaped test specimen using a scaling factor, χ-factor, to convert the ring load Fring into hoop stress σθ, and is written as σ θ = χ F ring tl , where t is the clad thickness and l is the clad length. The predicted stress–strain curves were found to agree well with experimental results for alloy Zr-4 over 10% strain.