Abstract
Fatigue failure is one of the essential phenomena to be considered in the design and integrity assessment of light water reactor plants and the methods for assessing its significance are given in the structural design standards. Decrease in fatigue strength due to environmental effect of high-temperature water ns reported and its introduction into the design standards gains a large importance. This issue and others related to fatigue evaluation for light water reactor plants have been discussed in a task group formed in the committee for power equipments codes organized in JSME. This report summarizes the updated infonnation on the activities in the task group including those on design fatigue curves, environmental effect as well e flaw tolerance approach.
