Development of environmental fatigue evaluation method for nuclear power plants in JSME code

Many examinations to evaluate the fatigue life reduction of structural materials of nuclear power plants in water simulating LWR coolants have been carried out. At the same time, the effects of several parameters on the fatigue life reduction have been determined quantitatively, since the first paper was published in Japan. Based on these results, the method to evaluate the fatigue damage for the materials exposed to the LWR coolant was developed. The MITI Guidelines (2000) and the TENPES Guidelines (2002) were issued for evaluating environmental fatigue damage at actual plants. The Environmental Fatigue Evaluation Method (EFEM) for Nuclear Power Plants (JSME S NF 1-2006) was established in the Codes for Nuclear Power Generation Facilities published by the JSME after reviewing the equations for the environmental fatigue life correction factor, Fen, and the evaluation techniques based on the updated knowledge at the time. The EFEM revised version has been drafted by incorporating the updated knowledge and is scheduled to be issued by the end of 2009. This paper introduces the outline of the revised JSME Codes and their technical bases concerning the effects of several parameters on the fatigue life reduction in the LWR coolant environment. (author)