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:
h. Material property based on the engineering stress-strain relationship. Critical Buckling Strength. The strength at which lateral displacements start to develop simultaneously with in-plane or axial deformations. If the function of a component support is not required during a plant condition, satisfaction of the design limits 3 of the support for that plant condition is not needed, provided excessive deflections or failure of the support will not result in the loss of function of any other safety-related system. System mechanical loadings include all non-self-limiting loadings and the effects resulting from constraints of free-end 4 displacements, but not the effects resulting from thermal or peak stresses generated within the component support. Because component supports are deformation sensitive in the performance of their service requirements, satisfying 5 these limits does not ensure the fulfilling of their functional requirements. Any deformation limits specified by the design specification may be controlling and should be satisfied. Because the design of component supports is an integral part of the design of the system and the component, 6 the designer should make sure that methods used for the analysis of the system, component, and component support are compatible. The designer of component supports should consider large deformations in the system or components. DG-1169, Page 6 C. REGULATORY POSITION The construction of ASME Code Class 1 plate-and-shell-type component supports, except snubbers, which this guide does not address, should follow the rules of Subsection NF of Section III of the Code, as supplemented by the following stipulations below:3 1. The classification of component supports should, as a minimum, be the same as that of the supported components. 2. The critical buckling strength should always limit the service limits for component supports designed by linear-elastic analysis. The calculation of critical buckling strength should use