Document: NRC Regulatory Guide
Document ID: a4944d20-ef6e-480b-a45d-14425bedd2e5
Document Type: regulatory_guide
Title: ASME Code Cases Not Approved for Use (Rev. 8)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2219/ML22196A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.193
CFR Part: 
CFR Title: 

Content:
0 DG-1408, Page 8 CODE CASE NUMBER TABLE 1 UNACCEPTABLE SECTION III CODE CASES SUMMARY DATE OR SUPPLEMENT/ EDITION cylindrical or tube specimens or even in the recent Electric Power Research Institute (EPRI)-sponsored component tests in Germany. • There is no information provided in the technical basis document about the operating conditions that were used to represent the worst-case environmental curve. Also, no information is provided in the basis document regarding the equation for the best-fit curve of the experimental data. • The technical basis document for the Code Case should address the effect of strain threshold and tensile hold time in fatigue evaluations. N-792-1 Fatigue Evaluations, including Environmental Effects, Section III, Division 1 This code case does not implement the latest methodology developed from NRC/RES research activities. That methodology was presented to ASME in May 2012, as reflected in the material posted in ADAMS at ML13008A005. There are also further adjustments to that information based on the finalization of our research efforts. Specifically, the six most significant differences between the Code Case and the latest NRC research are as follows: a. Carbon and Low-Alloy Steel Fatigue Curve: Code Case, Figure-2100-1, Figure-2100-1M, and Table-2100-1, define the design fatigue air curve for carbon and low-alloy steels. Both material types are combined into one fatigue curve, whereas the NRC approach defines a separate fatigue curve for each material type. The code case fatigue curve matches the design fatigue air curve currently in Section III, Appendix I (2011 Addenda). The Code Case fatigue curve does not match the carbon or low-alloy steel design fatigue air curves from the initial revision of NUREG/CR-6909 (which are the same curves the NRC intends to use in NUREG/CR-6909, Revision 1) because the Code Case fatigue curve uses a margin of 20 on cycles, whereas the NRC curves use a margin of 12. The Code Case design fatigue air