Crack propagation in high strain regions of a steel containment

During a severe accident, a containment may develop a controlled relatively small leak before the pressure reaches the point where general rupture of the shell occurs. Another hypothesis states that an overall failure will occur with total release of the vessel contents. This work represents a preliminary study to predict crack propagation from an initially small defect in a high strain location in a typical steel containment. The J integral approach is used. A virtual crack extension method for calculating J is developed for use with general finite element programs. Two through cracks with different lengths were found to be unstable at the pressure which caused a surface crack to propagate through the containment thickness. In other words, the resulting through crack will not be stable and general failure will occur with the almost instantaneous release of the vessel contents