Fretting Wear Between Zirconium Alloy Cladding Tube and Foreign Object in Simulated Primary Water of Pressurized Water Reactor

Abstract In the nuclear industry, fretting wear is one of the primary causes of nuclear fuel leakage and presents a significant safety concern. Therefore, investigating the fretting wear mechanisms of zirconium alloy fuel cladding tubes is crucial for ensuring the safe and stable operation of nuclear power plants during service. The wear damage of fuel cladding tubes caused by foreign objects is one of the typical failure modes and has attracted extensive attention from numerous scholars. In this study, the sliding fretting wear experiments between zirconium alloy and 316L stainless steel foreign objects were conducted in a simulated primary water environment of a pressurized water reactor (PWR). The experimental environment consisted of a boric acid-lithium hydroxide aqueous solution, with the experimental temperature and pressure set at 311°C and 15.5 MPa, respectively. During the experiment, fretting data were recorded, and the damage surfaces were characterized and analyzed using field emission scanning electron microscopy (FE-SEM). In addition, the wear coefficient was calculated using the Archard and energy model. The results indicate that, under constant frequency and normal load, the wear volume and wear coefficient increase with increasing displacement amplitude (wear power). As the displacement amplitude increased from 50 μm to 100 μm, the wear volume increased from 3.0×106μm3 to 7.2×106μm3. Based on the Archard model and the energy model, this study respectively calculated and comparatively analyzed the wear coefficients. Based on the above experimental results, further understanding of material wear behavior under actual operating conditions can facilitate the optimization of material selection and design, thereby extending equipment lifespan and enhancing operational efficiency.