Thermal Fatigue Analysis Of The Shaft Surface Of Nuclear Reactor Coolant Pump

Nuclear reactor coolant pump (RCP), called as the "heart" of the nuclear reactor, is the key equipment of the first circuit within the reactor. Its main function is to provide the power to deliver the coolant and discharge the heat generated. The RCP shaft, as one of the most important components in the RCP rotor system, is working under the environment of high-speed, high-temperature, high-pressure and strong-radiation. The stable operation of the shaft has a great important influence on the safety and reliability of RCP, even the whole reactor. Thermal fatigue problems and related researches of the RCP shaft caused by frequent thermal shock load of coolant are carried out in this dissertation.The RCP shaft usually works at a high temperature of about300℃and often endures the thermal shock effect caused by the cooling water. This is the main reason to initiate the fatigue cracks on the shaft surface. Therefore, it is very significant to predict the thermal fatigue life for the RCP shaft. In this dissertation, the transient temperature and thermal stress of the RCP shaft structure during the thermal shock process are analyzed. Influences of the thermal shock parameters, including shock temperature of cooling water, length of the shock area, shock frequency and liquid film thickness, on the thermal stress and fatigue life are studied using numerical simulation method. It is found that the fatigue cracks initiate from the outer surface, followed by propagating to the inner gradually, and the shock temperature, length of the shock area, shock frequency and liquid film thickness have significant effects on the thermal stress and fatigue life regularly.This dissertation is expected to establish a complete analysis system for thermal fatigue analysis of RCP shaft, the results obtained can provide reference for the shaft design and theoretical basis or criteria for the prediction of thermal fatigue life of RCP shaft.