Session: CS-07-01 Recent Developments in ASME Codes and Standards I

Paper Number: 61295

Start Time: Wednesday, July 14, 2021, 05:00 PM

61295 - ASME Section III Standards Committee Fatigue Action Plan 

Section III of the ASME Boiler and Pressure Vessel Code provides rules of the evaluation of cyclic loading that includes fatigue.  These rules were first developed in the 1960s along with the development of the original Section III Code.  Since then, technology and analytical advancements have improved our understanding of the fatigue phenomenon.  As an example, the developments in environmentally assisted fatigue (EAF) have become a major consideration in the low-cycle fatigue for light water reactors and plant life extension. 

Fatigue usage has an outsized impact on the overall cost and complexity of nuclear plants, which goes beyond just the qualification of ASME component.  For example, pipe break locations, pipe whip restraints, and In-service Inspections (ISI) are, in part, based on fatigue analysis results.  Therefore, it is important that fatigue analyses provide the most realistic assessment with appropriate conservatism.

The Section III Standards Committee has been working to keep the Code up to date with the latest research, analysis tools and fatigue data.  In 2017, a Fatigue Steering Committee was formed to provide a venue for stakeholders to identify and coordinate development of advanced fatigue design criteria, analysis methods, and their associated physical and thermo-mechanical properties for application to Section III of the ASME BPV Code. The stakeholders include many international organizations such as Japan Society of Mechanical Engineers. Many PVP papers have been used as the basis for the Fatigue Action Plan items. The Fatigue Steering Committee completed its work in 2019 with the adoption of a Fatigue Action Plan, which provided a vision for advanced fatigue approaches.  The Fatigue Action Plan recommended specific Code actions and activities to guide and coordinate the Code actions in the area of fatigue.

This paper will outline the overall Fatigue Action Plan and provide an update on the progress.  Section III already accomplished several actions on the Fatigue Action Plan by publishing numerous Code Cases and Code revisions that have improved the analysis tools available to designers to address fatigue.  This paper provides an overview and introduction to these Code Cases as well as to other tools a designer may utilize in a fatigue analysis.

The Fatigue Action Plan was largely based on addressing the need for the light water reactor fleet to address low cycle thermal fatigue.  The Committee recognizes that going forward the Fatigue Action Plan must also address the needs of the growing advanced reactor community as well as other users of the Code.  The paper will discuss these needs and the Section III plans to meet these future needs.

Presenting Author: Suzanne McKillop MPR Associates

Authors:

Suzanne McKillop MPR Associates
Robert Keating MPR Associates
Paul Donavin Engineering Management