When a flaw is detected in a stainless steel piping system of a nuclear power plant during in-service inspection, the limit load estimation method provided in codes such as ASME Section XI or JSME S NA-1-2008 can be applied to evaluate the integrity of the pipe. However, in the current editions of these codes, a limit load estimation method is only provided for pipes containing a single flaw. Independent multiple flaws, such as stress corrosion cracks, have actually been detected in the same plane of stainless steel piping systems. In this paper, a failure estimation method by formula is proposed for any number and arbitrary distribution of multiple independent circumferential flaws in the same plane of a pipe. Using the proposed method, numerical solutions are compared with experimental results to validate the model, and several numerical examples are provided to show its effectiveness.

Issue Section:
Design and Analysis
Keywords:
crack detection, inspection, nuclear power stations, pipes, stainless steel, stress analysis, stress corrosion cracking, multiple flaws, collapse bending stress, failure membrane stress, limit load criterion, fitness for service
Topics:
Collapse, Failure, Pipes, Stress, Symmetry (Physics)
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