Session: CS-08-02 ASME Code Section XI Activities-2

Paper Number: 125188

125188 - Stress Intensity Factor Solution Comparison for Very Long Circumferential Flaws in Cylinders Using Finite Element Analysis 

Section XI of the ASME Boiler and Pressure Vessel Code provides analytical evaluation procedures to determine the acceptability of flaws detected during in-service inspection of structural components and piping. Linear elastic fracture mechanics-based evaluation procedures require calculation of the stress intensity factor. Article A-3000 of Appendix A in Section XI provides closed-form relations for the stress intensity factor influence coefficients at both the deepest and surface points of the flaw, which were developed based on tabular data in API 579-1/ASME FFS-1 2007. The API 579-1/ASME FFS-1 2007 data do not cover very long flaws, e.g., flaws close to being fully circumferential flaws.  Stress intensity factor solutions are provided for fully circumferential flaws in Article A-3000, but there is no guidance on evaluating very long flaws that are beyond the current closed form solutions and still fall short of being fully circumferential.  Finite element calculations have been performed to obtain stress intensity factors for very long circumferential flaws in cylinders. The finite element results are used to assess the applicability of the current closed-form relations in Section XI Appendix A to very long circumferential flaws on the inside and outside surfaces of cylinders. The paper presents the finite element results and assessment of the applicability of the current Section XI equations.

Presenting Author: Nathan Glunt Electric Power Research Institute

Presenting Author Biography: Nate Glunt is a Principal Technical Leader within the Materials Reliability Program (MRP) at the Electric Power Research Institute (EPRI). Prior to joining EPRI, Glunt was a Design Engineer at V.C. Summer Unit 1 with responsibility for piping design basis oversight and plant modification design and implementation. Additional responsibilities included thermal fatigue program management and operational transient monitoring for ASME Class I components.

Glunt also has experience as a Senior Fracture Mechanics Engineer with Westinghouse Electric Company specializing in flaw evaluation support for nuclear power plants. He was responsible for performing structural integrity and crack growth evaluations for nuclear power plant piping, nozzles, vessels, head penetrations, and associated welds based on the ASME Section XI Code. An additional area of focus was mitigation methods for primary water stress corrosion cracking.

Glunt has a Bachelor of Science degree in Mechanical Engineering from North Carolina State University and is a Professional Engineer in the State of South Carolina.

Authors:

Nathan Glunt Electric Power Research Institute
Steven Xu Kinectrics
Russell Cipolla Intertek