Fretting Wear Behavior of ATF Cladding against Surface-Treated Spacer Grids

The Accident-Tolerant Fuel (i.e., ATF) could be defined as new fuel system that will tolerate the loss of active cooling in the core for a considerably longer period of time and to higher temperatures than the current fuel system while maintaining or improving fuel performance during normal operations. Many researcher published a paper including an outstanding corrosion resistance of ATF cladding candidates in high temperature steam when compared with current Zrbased fuel claddings. Lee et al. also proposed that the supporting materials (i.e., spacer grid) for ATF cladding candidates should be the same materials from the results of the tribological experiments. However, these candidates should be proven that there are no potential hazards, which experienced in Zr-UO₂ fuel system under normal operating conditions such as gridto-rod fretting (GTRF) regardless of their higher performances in simulated severe accident conditions. For this present work, the fretting wear behavior of a CrAl-coated cladding candidate manufactured by an Arc Ion Plating (AIP) method was examined using three kinds of surface-treated spacer grids in room temperature water. The objectives are to compare the wear resistance of ATF cladding with different spacer grids and to propose an exclusive spacer grid candidate for ATF claddings.