Method of Life Prediction for Low Cycle Fatigue in PWR Primary Pipe Material

An experimental study on the fatigue behavior of the NPP PWR primary pipe material Z3CN20.09M made in China is performed on a group test of low-cycle fatigue under room temperature and elevated temperature of 350℃.The Manson-Coffin equation,simple tensile prediction model,Ostergren model and three-parameter power function for low cycle fatigue（LCF） are investigated.The prediction results show that the life prediction capability in elevated temperature is weaker than that in room temperature for all models except the simple tensile prediction model.The simple tensile prediction model gives worst results,most of its predictions are on the non-conservative side,while the Ostergren model presents best predictions for room fatigue tests,and the three-parameter power function yields a good result in life prediction for ele-vated temperature fatigue tests.