Abstract
The boiling water reactor (BWR) includes many internals with complex welded parts. It is necessary to develop an in-service inspection rule for the internals based on fracture mechanics concepts. In this paper, the stress intensity factors of a surface crack in a pipe penetrating a thick plate with a stub tube were estimated. This geometry was chosen to model the control rod drive housing in a Boiling Water Reactor. Numerical and simplified methods were applied for the calculation of the stress intensity factors. The simplified methods were developed for the geometry of pipes and plates and gave comparable results to the numerical methods in some cases. In other cases the stress intensity factors estimated by the simplified methods were higher than by the numerical methods. To decrease the conservatism for the simplified method, a modification factor obtained by two-dimensional numerical analysis was proposed. By using the modification factor, the simplified methods gave close results to the numerical method.
