This paper presents burst pressure tests of two ex-service, 2 1/2-inch, SA-106 Grade B pipe bends with multiple part-through-wall axial cracks. The two pipes tested were sections of outlet feeders that were removed from the Point Lepreau Generating Station after 18.6 and 19.5 effective full-power years of service. The field of cracks was tightly distributed in the longitudinal and transverse directions of pipe bends on both inside surface and outside surfaces. The total length of the crack fields were 40 mm and 100 mm, respectively. The deepest crack was 73% through-wall. The burst pressure tests were performed at 90°C. The failure pressure was more than 4 times the design pressure. Post-test metallurgical examinations revealed mixed mode failures on the main fracture surface. The failure of the specimens was controlled by local plastic collapse of the ligaments of a small number of the deepest cracks in the field of cracks.

This content is only available via PDF.
You do not currently have access to this content.