Comparison of Fatigue Life Analysis Methods
Comparison of Pressure Vessel Fatigue Codified Design Rules Based on S-N Approach
The Cooperation in Reactor Design Evaluation and Licensing (CORDEL) Working Group was established in 2007 to promote the development of a worldwide regulatory environment where internationally standardized reactor designs can be widely deployed without major design changes due to national regulations.
The Mechanical Codes and Standards Task Force (MCSTF) of the CORDEL Working Group was set up in 2011 to collaborate with the Standards Development Organizations Board (SDO Board) and the Multinational Design Evaluation Program (MDEP) Codes and Standards Working Group (CSWG) on the international convergence of mechanical codes and standards related to the design of nuclear power plant components important to safety. It has worked to date principally in three areas: qualification of non-destructive examination (NDE) personnel; non-linear analysis design rules; fatigue analysis and design rules.
In the area of fatigue analysis and design rules, the topics identified by the MCSTF for investigation with a view to harmonized approaches are: differences in nuclear mechanical design codes; pressure vessel and piping fatigue design approach; fatigue crack growth analysis; and environmental effects on fatigue.
This report, the first of four, reviews and compares the current code and standard requirements of major nuclear design codes in the area of fatigue analysis and design rules based on the S-N approach against ASME III NB. The report focuses on Class 1 vessels of Light Water Reactor (LWR) plants.
The main findings of this report can be summarised as follows:
- The nuclear design codes and standards analysed are equivalent to ASME III NB in most areas.
- The requirements of RCC-M are either the same as - or equivalent to - ASME III NB except in the definition of the fatigue curve, the plasticity correction (Ke) factor, and the method for assessing local structural discontinuities.
- The requirements of KEPIC MN MNB are the same as those of ASME III NB in all areas.
- The requirements of the JSME S NC1 are either the same as - or equivalent to - ASME III NB, except in the definition of the fatigue curve, the plasticity correction (Ke) factor, and the fatigue strength reduction factor (FSRF).