Surface Crack Growth in Reactor Header Tee under Cyclic Pressure

摘要

High stress concentration occurs at inner corner in the piping tee junction. A semi-elliptical surface crack is postulated at inner surface of piping tee corner for Leak - Before - Break design. Other type of crack shapes are also investigated before arriving at semi-elliptical shape. The surface crack growth as a result of pressure cycles, is studied. The cracks oriented in axial and circumferential direction at tee corner are considered. The results show that for the postulated crack the number of cycles required is very high for propogation through the thickness.