Abstract：To achieve fatigue life prediction reactor coolant pump impeller, a calculation model based on fluid-thermal-structure interaction was established considering the harsh operating conditions of high temperature and high pressure of the impeller. The pressure load and temperature load of the internal flow field of the reactor coolant pump at different times were numerically simulated using ANSYS CFX software. The transfer of pressure load and temperature load to the structure was realized in ANSYS Workbench, and then the research on the dynamic response fatigue load of the impeller was carried out. Statistical analysis was conducted on the load data of dangerous parts of the impeller using the rain-flow counting method, and further combining with Palmgren-Miner theory, the minimum fatigue life cycle of the impeller of the reactor coolant pump was predicted. The results show that the impeller is subjected to periodic alternating stress during rotation. There are four stress concentration areas on the impeller, which are the interfaces between the inlet and outlet edges of the blade and the shroud and hub. The maximum stress occurs at the interface of the blade outlet and the shroud, with a maximum value of 142.57 MPa. The occurrence time of stress wave crest and wave trough of dangerous parts of blade is basically the same. The fatigue on the impeller is high cycle fatigue, and the fatigue failure first occurs at the interface between the inlet edge of the blade and the hub. The calculated fatigue life of the impeller is 277.84 years. The research results can provide useful reference for the dynamic strength optimization and fatigue design of impellers.
