Benchmark Mechanical Test Results of Westinghouse Zirconium Cladding and Irradiated Testing Readiness

There is currently interest in advanced fuel-cladding alloys to support high burnup by reducing the impact on the fuel-cladding structure from environmental degradation. While the new alloys may reduce the impact of environmental degradation, their mechanical integrity must be quantified to ensure that they improve or maintain current safety margins. Importantly, the new alloys must be tested under conditions imposed on them by commercial reactors. However, to understand the out-of-reactor performance of new alloys, benchmark data must be provided to understand the impacts of the test methodology relative to standard ASTM testing and to provide a baseline to evaluate performance. To that end, Westinghouse has provided as-received industry-grade zirconium-alloys cladding tubes that will complement future tests with irradiated cladding tubes of the same materials. In this work, zirconium-alloy cladding tubes were machined into axial tension test (ATT) and ring tension test (RTT) mechanical test geometries using a CNC end mill that has been inserted into the hot cell to machine future specimens from commercially irradiated cladding tubes. Details on machining precision and impacts on specimen geometry are included. Following machining, mechanical tests were performed at ambient temperature and 385°C. ATT mechanical test data was evaluated by comparing to ASTM axial specimen data and utilizing digital image correlation to measure strains on the sub-sized gages. RTT mechanical test data was understood by utilizing digital image correlation and applying engineering research to understand friction effects. Details on hot cell manufacturing, inspection, and testing capability with DIC for irradiated counterpart specimens will be included.