Limit loads of dissimilar metal welded joints for joining safe end to pipe-nozzle of nuclear pressure vessel

Limit load is an important parameter in structural integrity assessment of cracked components. In this work, the limit loads of an actual dissimilar metal welded joint (DMWJ) for joining safe end to pipe-nozzle of a reactor pressure vessel have been investigated based on extensive three-dimensional finite element analyses. The effects of a wide range of crack sizes and locations on limit loads have been analyzed. The results show that for shorter and shallower cracks, the limit loads are mainly determined by global plastic yielding of safe end material with the lowest yield strength, and the crack sizes have nearly no effect on them. For longer and deeper cracks, the limit loads are mainly determined by general yielding of the ligament area ahead of a crack. With increasing crack length or depth, the limit load decreases. With moving crack locations from the pipe-nozzle through buttering and weld metal to safe end, the limit load decreases. The normalized limit load solutions for the DMWJ are given.