SYMPOSIA PAPER Published: 01 January 1983
STP36774S

Engineering Methods for the Assessment of Ductile Fracture Margin in Nuclear Power Plant Piping

Source

When a crack is discovered during inspection of a piping component in a nuclear power plant, the decision on replacement is dependent on the available design margin of the pipe in the presence of the crack. This paper describes the development of engineering methods to assess the design margin in cracked pipes. Procedures are outlined to evaluate cracks in piping, using methods consistent with the American Society of Mechanical Engineers (ASME) Code design basis, and to develop failure diagrams for piping. A criterion based on net section collapse is shown to predict adequately the load capability of piping with cracks. The predictions of the net section collapse approach are shown to be consistent with results from elastic-plastic fracture analysis based on J-integral and R-curve methods. Finally, the methodology is used to recommend acceptance criteria for flaws in power plant piping. The proposed criteria assure that the minimum safety margins inherent in the ASME Code are preserved during operation. Since allowable flaw sizes can be determined using information already available in piping stress reports, the proposed criteria offer a simple conservative method for assessing flaws in piping.

Author Information

Ranganath, S
General Electric Co., San Jose, Calif.
Mehta, HS
General Electric Co., San Jose, Calif.
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Details
Developed by Committee: E08
Pages: 309–330
DOI: 10.1520/STP36774S
ISBN-EB: 978-0-8031-4870-3
ISBN-13: 978-0-8031-0726-7