Development of an Environmental Fatigue Evaluation Method for Nuclear Power Plants in JSME Code

摘要

Many examinations concerning the fatigue life reduction for structural materials of nuclear power plants in simulated LWR coolant have been performed, and the effects of several parameters on fatigue life reduction have been quantified in the time since the first paper on this subject was recognized in Japan. Based on these results, methods to evaluate fatigue damage for materials exposed to LWR coolant have been developed. The MITI Guidelines (2000) and the TENPES Guidelines (2002) were issued for evaluating environmental fatigue damage in operating plants. The Environmental Fatigue Evaluation Method (EFEM) for Nuclear Power Plants (JSME S NF1-2006) was established in the Codes for Nuclear Power Generation Facilities by the JSME by reviewing the equations for the environmental fatigue life correction factor, F _(en) , and the techniques for evaluation based on the most up-to-date knowledge at the time. A revised version of the EFEM was drafted by incorporating updated knowledge and issued by the end of 2009. This paper outlines the revised JSME Codes and technical bases, and discusses the effects of several parameters on fatigue life reduction in such environments.