Research On Mechanicals-Thermal Fatigue Of The Shaft In A Reactor Coolant Pump

The Reactor Coolant Pump(RCP),as the continuous power source in the nuclear plant, needs to undertake harsh environment. Ensure of the safe operation is a keypoint problem that has to be solved. To meet the great needs of the independent manufacturing in reactor coolant pump, thermal fatigue problem caused by the turbluence and thermal shock is disscused.The effect of mechanical stress is discussed in the normal loadcade,Considering the detailed load,it is founded that the mechanical load is a slight factor,and it is not the main factor of the fatigue.The mechanism of convective heat transfer is elaborated,from the result of equvialent model we can get the film-cofficient,and an example is listed.The result illustrates that the equivalent model can explain the mechanism of the convective heat transfer reasonably.Next the classic method is introduced to get the film-cofficent and the advantage and disadvantage is compared.The transisent thermal conduct and thermal stress analysis are completed by the software of abaqus.The results illustrate that the thermal stress is more obvious than the mechanic stress. The mixing area near the shaft may be the main reason of the fatigue. By modifying the keyword file we can get the result of stress binary file,it provides the complete file for fatigue analysis.The relationship between the stress and conduction time, enviorenment temperature,film-coefficient is presented by single variables analysis.The combined factor relationship is given by the way of responce surface method(RSM).Finally the distribution of thermal stress in the shaft is given. Next the distribution of stress is given by the mechanicals-thermal analysis,Then the fatigue analysis is performed.The result illustrates the thermal fatigue is coincident with the practical condition.So we can conclude that the existence of the thermal stress and the mixing area is the main factor of fatigue.Last we analyse the whole lifetime of the improved shaft sleeve,The lifetime estimation of the shaft is given.This thesis provides a complete flow chart of the shaft fatigue analysis,neccesary theory and the improved protection of the shaft.