Abstract
Recently, incidents of SCC in Ni-base alloy weld metal of BWR components have been reported. Structural integrity assessment should be. performed based on the Rules on Fitness-for-Service for Nuclear Power Plants of the Japan Society of Mechanical Engineers Code (JSME FFS Code). However, fatigue crack growth analysis for Ni-base alloy is impossible since the fatigue crack growth rate curves in air and BWR environment are not prescribed yet in JSME FFS Code. In this study, fatigue crack growth tests in air were performed for Ni-base alloy weld metal. Based on the test data, fatigue crack growth rate curves with ΔK_<th> were investigated. The curve in Paris' region was regarded as the same curve despite the difference of the test temperature and the stress ratio. On the other hand, ΔK_<th> was regarded to depend on the test temperature and the stress ratio.
