Document: NRC Regulatory Guide
Document ID: 2e29f931-cdf2-4faa-a9e4-5d7cb237e57f
Document Type: regulatory_guide
Title: Service Limits and Loading Combinations for Class 1 Plate-and-Shell-Type Component Supports + HISTORY – HISTORY 10/2006 – DG-1169 , Proposed Revision 2
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063000484.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.130
CFR Part: 
CFR Title: 

Content:
ceptability, ASME Section III,” 2 provides guidance for the acceptability of ASME Code, Section III code cases and their revisions, including ASME Code Cases N-71 and N-249. Code cases identified as “Conditionally Acceptable Section III Code Cases” are acceptable, provided that they are used with the identified limitations or modifications. DG-1169, Page 3 Design by Linear-Elastic Analysis Tables 2A, 2B, 4, U, and Y-1 in Subpart 1 of Part D of Section II and Tables 1, 3, 4, and 5 in the latest accepted versions of ASME Code Cases N-71 and N-249 give the material properties 2 when the linear-elastic-analysis method is used to design Class 1 plate-and-shell-type component supports. m These tables list values at various temperatures for the design stress intensity S , minimum yield strength y u S , and ultimate tensile strength S . NF-3522 and NF-3622 limit the primary stress for Service Levels A, B, and C to less than or equal to one-half of the critical buckling strength of the component support at temperature. Similarly, F-1331.5(a) limits the increase for Service Level D to two-thirds of the critical buckling strength of the component support at temperature. Because buckling prevents “shakedown” in a load-bearing member, it should be regarded as controlling for the Level A through Level D service limits. Also, buckling is the result of the interaction of the geometry of the load-bearing member and its material properties y (i.e., elastic modulus E and minimum yield strength S ). Because these material properties both change y with temperature, calculation of the critical buckling stresses should use the values of E and S of the component support material at temperature. Allowable service limits for bolted connections are derived on a different basis that varies with the size of the bolt. For this reason, the increases permitted by NF-3221.2 and F-1332 of Section III do not directly apply to bolts and bolted connections. For bolts, allowable increases for