Effect of Impact Block Shape and Material on Impact Wear Behavior of Zr-4 Alloy Cladding Tube

Abstract

In a pressurized water reactor nuclear power plant, metal foreign matter in the rod–rod gap of the fuel assembly is constantly rubbed and collided with the fuel rod under continuous scouring of the coolant, resulting in wear to the fuel rod and even leakage of the perforation. In this work, the effects of different debris shapes and materials on the impact wear behavior of Zr−4 alloy tubes were studied through the dynamic response and damage of Zr−4 alloy tubes under cyclic impact. The results show that the sharper the shape of the impact block, the higher the wear rate of the Zr−4 alloy tube. Although the energy absorption rate of SA 508−A during the impact process is high, most of the energy is used for the wear of the impact block itself and the formation and peeling of the wear debris accumulation layer, and the damage to the Zr−4 alloy tube is small. The wear debris generated by the Zr−4 impact block is not easy to oxidize, and the wear caused by the cyclic impact is more serious. After the Zr−4 impact block cyclically impacts the Zr−4 alloy tube 200 w times, the Zr−4 alloy tube will be perforated due to wear. The oxidation and accumulation of wear debris and the wear mechanism in the impact process are mainly abrasive wear and surface peeling behavior. The occurrence of cutting and wear removal will promote the wear and thinning of the tube wall of the Zr−4 alloy tube, and the tube wall is easily perforated after thinning.