Investigation on Irradiation Resistance of Anti-Galling Lubricant for High Temperature Fasteners of Nuclear Power Plant

Lubricant grease is a special material commonly used in the field of nuclear power plant. It is widely used in the sliding fit and press fit parts of bolts, studs and valves to prevent thread wear, seizing as well as stress corrosion cracking of fasteners during assembly, service and disassembly. In this paper, the performance of lubricant materials such as wear resistance and high temperature oxidation resistance under irradiation environment were studied. The results show that the lubricant grease does not change significantly and there is no grease stratification after irradiation with 0.1MGy integrated irradiation dose. However, after irradiation with 10MGy integrated irradiation dose, the irradiation has an obvious destructive effect on the oxidation resistance performance of the grease, and the grease appears obvious stratification. With the increase of irradiation dose, the thermal decomposition temperature first decreases and then increases. Under 0.1MGy irradiation dose, the thermal decomposition loss of the sample changes little, but at 10MGy irradiation dose, a large amount of mass loss occurred, up to more than 80%. The four-ball friction experiment shows that its extreme pressure resistance improves with the increase of irradiation dose, and the sintering load increases. These data provide technical guidance for the long-term reliability of nuclear power fastener materials in service.