Session: CS-22-01 Repair and Replacement Activities to Maintain Component Integrity

Paper Number: 106137

106137 - History and Technical Scope of Code Case N-513 

ASME Section XI Case N-513, Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping and Gate Values [2-1], is one of the most widely implemented code cases within the U.S. nuclear industry.  The primary purpose of the code case is to provide evaluation criteria for flaws within moderate energy, safety-related piping to permit continued plant operation without repair/replacement until the next scheduled refueling outage.  Invocation of the code case allows utilities to avoid an unscheduled plant shutdown provided structural integrity requirements are met. Periodic examinations of the flaw during the temporary acceptance period is required by N-513 to ensure the flaw has not grown beyond the acceptable flaw size. N-513 is typically implemented to disposition flaws found in service water piping made of carbon steel that is exposed to raw water where active corrosion mechanisms exist.  The Code Case can also be applied to stainless steel and nonferrous material components.

The purpose of this paper is to provide a history of N-513, its technical scope, current ASME Code and regulatory status, as well as proposed changes for an upcoming revision.  This paper also provides a secondary benefit of consolidating the history and development of this important nuclear industry flaw evaluation methdology for traceability and knowledge transfer purposes.

Presenting Author: Stephen M. Parker Structural Integrity Associates

Presenting Author Biography: Mr. Stephen Parker is a consultant currently working for Structural Integrity Associates where he specializes in stress analysis and fracture mechanics. He is a member of the ASME Boiler and Pressure Vessel Code Working Group on Pipe Flaw Evaluation and is the secretary for the Task Group on Code Case N-513 Revisions. Over the last 6 years of his career, a primary focus of his time has been assisting nuclear utilities on Code Case N-513 evaluations, including implementations, training, and software packages.

Authors:

Stephen M. Parker Structural Integrity Associates
Steven L. Mccracken Electric Power Research Institute
Robert O. Mcgill Electric Power Research Institute
Ioannis D. Patten Structural Integrity Associates