THE FRACTURE BEHAVIOR OF CYLINDERS WITH AXIAL SURFACE CRACKS UNDER STRONG THROUGH-WALL BENDING STRESSES

Reactor pressure vessel (RPV) may subject to strong through-wall bending stresses under some situations, such as pressurized thermal shock (PTS) transients. The fracture behaviors of cylinders with internal axial surface cracks under PTS conditions are investigated in this paper. A typical PTS transient is selected to simulate the bending stress. The critical crack sizes including crack depth and crack surface length for a given cylinder is analyzed for the assumed PTS transient using the critical crack depth diagram method. Crack initiation and growth at both the deepest and surface points are considered and the effect of the crack growth at surface point on the growth along the wall-thickness is investigated. The results show that the crack initiation and growth at the surface point should be considered and the critical crack depth for the assumed transient may depend on the fracture behaviors at both the deepest and surface points.