Fatigue Evaluation for Section III, Class 1 Components Using Flaw Tolerance Method to Consider Environmental Effects

2015 ◽  
Author(s):  
David Roarty ◽  
Wolf Reinhardt ◽  
David Dewees
Keyword(s):  
Fatigue Crack ◽  
Environmental Effects ◽  
Design Assessment ◽  
Flaw Tolerance ◽  
Design Life ◽  
Tolerance Approach ◽  
Class 1 ◽  
Fatigue Evaluation ◽  
Tolerance Method ◽  
Type 304

An ASME Section III Task Group (TG) was formed in 2012 to develop alternate rules for the design assessment of Section III Class 1 nuclear components subject to fatigue service with environmental effects. A Section III Code Case has been proposed with the purpose of providing a method for performing fatigue evaluations of Class 1 components when the effects of a light water reactor environment on fatigue life are judged to be significant and cumulative usage factor (CUF) limits may not be satisfied. The Code Case implements a flaw tolerance approach by postulating that a fatigue crack initiates at the beginning of life and is subjected to fatigue crack growth under the specified design cycles. It must be demonstrated that the crack would remain stable with set margin throughout the design life of the component or part under consideration, and would remain confined to an acceptable fraction of the wall thickness. At this time, the application is limited to type 304/304L and 316/316L austenitic steel. This paper discusses the methodology and technical background of the proposed Code Case.

ASME Section III Flaw Tolerance Sample Problem for Fatigue Design of Nuclear System Components

2014 ◽  
Author(s):  
David J. Dewees ◽  
Paul Hirschberg ◽  
Wolf Reinhardt ◽  
Gary L. Stevens ◽  
David H. Roarty ◽  
...  
Keyword(s):  
Environmental Effects ◽  
Water Environment ◽  
Sample Problem ◽  
Design Assessment ◽  
Thermal Transients ◽  
Flaw Tolerance ◽  
Initial Task ◽  
Class 1 ◽  
Fatigue Evaluation ◽  
Technical Basis

An ASME Section III Task Group (TG) was formed in 2012 to develop alternate rules for the design assessment of Section III Class 1 nuclear components subject to fatigue service with environmental effects. Specifically, a flaw tolerance approach is being investigated based on similar methodology to that found in ASME Section XI Nonmandatory Appendix L. A key initial task of the TG (which reports to the Section III Working Group on Environmental Fatigue Evaluation Methods) was to develop and solve a detailed sample problem. The intent of the sample problem was to illustrate application of proposed rules, which will be documented as a Section III Code Case with a supporting technical basis document. Insights gained from round robin solution of the sample problem are presented and discussed in this paper. The objective of documenting the findings from the sample problem are to highlight the observed benefits and limitations of the proposed procedures, particularly how rules typically associated with in-service experience might be adapted into design methods. The sample problem is based on a heavy-walled stainless steel nozzle that meets cumulative fatigue usage requirements in air (i.e., usage factor, U, without reactor water environment effects less than unity), but fails to meet usage factor requirements when environmental fatigue effects are applied. The sample problem demonstrates that there is a class of problems dominated by severe thermal transients where fatigue initiation is predicted based on elastic methods including environmental effects, but fatigue crack propagation results are acceptable. Preliminary conclusions are drawn based on the results of the sample problem, and the next steps are also identified.

Environmental Fatigue Evaluation for Primary Components of APR1400 Reactor Coolant System

2010 ◽  
Author(s):  
J. M. Kim ◽  
K. W. Kim ◽  
K. S. Yoon ◽  
S. H. Park ◽  
I. Y. Kim ◽  
...  
Keyword(s):  
Environmental Effects ◽  
Integral Method ◽  
Power Reactor ◽  
Light Water Reactor ◽  
Outlet Nozzle ◽  
Design Life ◽  
Class 1 ◽  
Asme Code ◽  
Fatigue Evaluation ◽  
Coolant System

USNRC Regulatory Guide (RG) 1.207 provides a guideline for evaluating fatigue analyses due to the environmental effects on the new light water reactor (LWR). The environmental correction factor (Fen) is used to incorporate the LWR environmental effect into fatigue analyses of ASME Class 1 components. In this paper, the environmental fatigue evaluation is applied to some primary components with 60 year design life of Advanced Power Reactor (APR1400). The materials sampled from Class 1 components are the low alloy steel for the reactor vessel (RV) outlet nozzle and the carbon steel for the hot leg which are attached to the outlet nozzle. The simplified method, time-based integral method and strain-based integral method are used to compute the Fen values. The calculated fatigue usage factors including the environmental effects are compared with those obtained using the current ASME Code rules. As the calculated cumulative fatigue usage factor considering environmental effects (CUFen) is below 1.0, there is no concern for the RV outlet nozzle to implement design for environmental fatigue effects.

Development of Fatigue Assessment Method Based on Flaw Tolerance Concept

2013 ◽  
Author(s):  
Seiji Asada ◽  
Takeda Shuhei ◽  
Taiji Hirasawa ◽  
Toshiyuki Saito ◽  
Itaru Saito ◽  
...  
Keyword(s):  
Power Generation ◽  
Nuclear Power ◽  
Evaluation Method ◽  
Assessment Method ◽  
Fatigue Assessment ◽  
Nondestructive Examination ◽  
Flaw Tolerance ◽  
Fatigue Evaluation ◽  
Tolerance Method ◽  
Operating Plant

The Japan Society of Mechanical Engineers (JSME) Committee on Power Generation Facility Codes recognizes the importance of fatigue evaluation methods based on the latest knowledge and is developing a fatigue evaluation method by flaw tolerance. The ASME B&PV Code Section XI has Non-mandatory Appendix L, “Operating Plant Fatigue Assessment” (hereinafter “App. L”), which provides a flaw tolerance method for fatigue evaluation when a cumulative usage factor (CUF) of a component is greater than 1.0. In order to develop a flaw tolerance method for the JSME Codes for nuclear power generation facilities, postulated initial flaws, capability of nondestructive examination, compatibility to rules and flaw tolerance codes are discussed.

Comparison of International Codes for a Fatigue Crack Growth Flaw Tolerance Sample Problem

2021 ◽  
Author(s):  
Gary L. Stevens
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Large Diameter ◽  
Sample Problem ◽  
Pressurized Water ◽  
Typical Application ◽  
Flaw Tolerance ◽  
Asme Code ◽  
The Impact

Abstract As part of the development of American Society of Mechanical Engineers Code Case N-809 [1], a series of sample calculations were performed to gain experience in using the Code Case methods and to determine the impact on a typical application. Specifically, the application of N-809 in a fatigue crack growth analysis was evaluated for a large diameter austenitic pipe in a pressurized water reactor coolant system main loop using the current analytical evaluation procedures in Appendix C of Section XI of the ASME Code [2]. The same example problem was previously used to evaluate the reference fatigue crack growth curves during the development of N-809, as well as to compare N-809 methods to similar methods adopted by the Japan Society of Mechanical Engineers. The previous example problem used to evaluate N-809 during its development was embellished and has been used to evaluate additional proposed ASME Code changes. For example, the Electric Power Research Institute investigated possible improvements to ASME Code, Section XI, Nonmandatory Appendix L [3], and the previous N-809 example problem formed the basis for flaw tolerance calculations to evaluate those proposed improvements [4]. In addition, the ASME Code Section XI, Working Group on Flaw Evaluation Reference Curves continues to evaluate additional research data and related improvements to N-809 and other fatigue crack growth rate methods. As a part of these Code investigations, EPRI performed calculations for the Appendix L flaw tolerance sample problem using three international codes and standards to evaluate fatigue crack growth (da/dN) curves for PWR environments: (1) ASME Code Case N-809, (2) JSME Code methods [5], and (3) the French RSE-M method [6]. The results of these comparative calculations are presented and discussed in this paper.

Fatigue evaluation of FV520B-I shrouded impeller blade with fatigue crack based on FEA and fracture mechanics

2020 ◽  
Vol 115 ◽  
pp. 104663
Author(s):  
Wang Jinlong ◽  
Yan Yangyang ◽  
Yu Jing ◽  
Wang Jingsi ◽  
Du Fengming ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fracture Mechanics ◽  
Impeller Blade ◽  
Fatigue Evaluation
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