Analysis and evaluation methodology of effect of light water reactor coolant environment on fatigue life of class 1 components

It is required that the fatigue analysis should be done for nuclear reactor class 1 components composing of the reactor pressure boundary. Based on worldwide researches, it is found that the fatigue design curves currently used in the analysis have no enough margins considering the coolant environmental effect, and the regulatory bodies in the world have paid high attention to it. General information related to the research background was introduced, and the NRC method and the related ASME activities were discussed. Possible ways are recommended to deal with the potential issues that may arise. (authors)