Session: CS-17-03 Fatigue Evaluation Method

Paper Number: 102692

102692 - Technical Revisions of Jsme Environmental Fatigue Evaluation Method 

   In Japan, environmental fatigue evaluation for LWR components are required in plant life management (PLM) from the regulatory side. The utilities are using JSME “Environmental Fatigue Evaluation Method for Nuclear Power Plants” (JSME S NF1).
   The first publication of JSMS S NF1 was 2006 Edition, and it was revised as 2009 Edition.
   After that, Subgroup on Fatigue Evaluation in the JSME Committee on Power Generation Facility Codes has developed three technical items for the JSME Environmental Fatigue Evaluation, and those have been approved by the Main Committee. Those revisions will be incorporated into 2022 Edition.
  The first one is design fatigue curves. The Japan Welding Engineering Society developed a new method for design fatigue curves based on the best-fit curves using tensile strength as a variable. In this method, several factors are considered for the correction of the fatigue curve such as the factors on stress and cycles by statistical analysis, fatigue strength reduction factor for surface finish effect, mean stress correction using the Smith-Watson-Topper approach and variable amplitude effect. The JSME Subgroup on Fatigue Evaluation has reviewed this method, and decided to incorporated it into the JSME Environmental Fatigue Evaluation with some modifications.
  The second one is environmental fatigue life correction factor, Fen for PWR components. A Japanese PWR utility project developed new Fen equations for stainless steels of PWR components. The JSME Subgroup on Fatigue Evaluation has reviewed them, and deiced to employ the Fen equation for base metal of stainless steels for applying to all stainless steels.
  The third one is Flaw Tolerance Approach for environmental fatigue evaluation. The JSME Subgroup on Fatigue Evaluation has developed this method.
  In this paper, the above three items are introduced.
 

Presenting Author: Seiji Asada Mitsubishi Heavy Industries Ltd

Presenting Author Biography: -Graduated from Kobe University in March 1987
-Master’s degree from Kobe University in March 1989
-PhD from Kobe University in March 2009
-Joined Mitsubishi Heavy Industries in April 1989.
-Since joined in Mitsubishi heavy Industries, I have been in charge of designing and development of Reactor Pressure Vessels. Especially I have made a lot of effort at stress analysis, fatigue analysis, irradiation embrittlement issue of RPVs, fracture mechanics, and so on.
-Chair of SDO (Standard Development Organization) Convergence Board
-Member: [ASME Code Committee] BPV III, SG on Component Design, WG on Environmental Fatigue Evaluation Method
[JSME] Subcommittee on Nuclear, SG on Design and Construction, SG on Fatigue Evaluation, and so on.

Authors:

Seiji Asada Mitsubishi Heavy Industries Ltd
Takao Nakamura Osaka University
Masayuki Kamaya Institute of Nuclear Safety System, Incorporated
Yukio Takahashi Tokyo University of Science