Degraded Piping Program: Phase 2, Semiannual report, April 1986-September 1986

Presented herein is the Fifth Semiannual Report of the US NRC's Degraded Piping Program - Phase II. The intent of this program is to experimentally validate and enhance available analytical methods for evaluating the mechanical behavior of nuclear power plant piping containing circumferentially-oriented defects. Fifty-one pipe experiments have been conducted to date. These and approximately 42 additional pipe experiments from other programs have been analyzed. In the analytical effort, a screening criterion has been developed to show when the net-section-collapse analysis is valid. This shows that even tough materials such as stainless steel can fail at less than net-section-collapse loads if the pipe diameter is sufficiently large. Numerous predictive J-estimation schemes have been evaluated and modified. A finite length surface cracked pipe estimation scheme has also been developed. Finite element analyses of specimens with welds suggest that the size of the weld relative to the specimen or structure size can affect the deformation J values. Supporting research efforts involve investigating geometry effects on J-R curves, as well as characterizing the material properties for each pipe tested.