Degraded piping program: Phase II: Sixth program report, October 1986--September 1987

Presented herein is an Annual Report of the US NRC's Degraded Piping Program---Phase II. This is the sixth program report on this program. Prior reports were semiannual reports. 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-seven pipe experiments have been conducted to date. These and approximately fifty 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 though 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 and incorporated into a computer code called NRCPIPE. This code provides a convenient way of analyzing cracked pipe with a number of currently accepted analytical methods. Supporting research efforts involve investigating geometry effects on J-R curves, as well as characterizing the material properties for each pipe tested. The significance of all of the efforts to date relative to pipe fracture analyses and flaw assessment criteria are discussed