F-1705 A Study of Evaluation Method of Stress Intensity Factor for Reactor Internals of Nuclear Power Plants

Abstract

To verify the evaluation methods of stress intensity factor for a surface crack in a complex welded joint in the reactor internals of nuclear power plants, the stress intensity factors evaluated by two proposed methods were compared with those by finite element analysis (FEA). The stress intensity factors obtained by the first evaluation method (evaluation method 1) based on the influence function method were higher than those by three-dimensional (3D) FEA for a surface crack in the T-joint. To improve the accuracy of the evaluation method 1, the second evaluation method (evaluation method 2), which modifies with the ratio of geometry function evaluated by two-dimensional FEA was proposed. The stress intensity factors obtained by evaluation method 2 are in a good agreement with those by 3D FEA.