Document: NRC Regulatory Guide
Document ID: 1d715751-9321-4481-a46f-4ff802a5efe0
Document Type: regulatory_guide
Title: Service Limits and Loading Combinations for Class 1 Linear-Type Supports + HISTORY – HISTORY 10/2006 – DG-1168 , Proposed Revision 2
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063000449.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.124
CFR Part: 
CFR Title: 

Content:
esign by Load Rating NF-3380 of Section III specifies the qualification of linear-type supports to Service Level A, B, and C limits, using load-rating criteria. F-1334.8 specifies the qualification of linear-type supports to Service Level D limits using load rating criteria. This guide provides additional guidance for determination of the Service Level D load rating. Design by Experimental Stress Analysis Although II-1430 in Appendix II to Section III defines the test collapse load for the experimental stress analysis method, the various levels of service limits for experimental stress analysis are not delineated. The method described in this guide remedies this deficiency. Large Deformation The design of component supports is an integral part of the design of the system and its components. A complete and consistent design is possible only when the interaction between the system, component, and component support is properly considered. When all three are evaluated on an elastic basis, the interaction is usually valid because individual deformations are small. However, if the design process uses plastic analysis methods, large deformations may occur that would result in substantially different stress distributions. When component supports are designed for loadings associated with the faulted plant conditions, Appendix F to Section III of the ASME Code permits the use of plastic analysis methods in certain acceptable combinations for all three elements. The selection of these acceptable combinations assumes that component supports are more deformation sensitive (i.e., their deformation in general will have a large effect on the stress distribution in the system and its components). Because large deformations always affect the stress distribution, care should be exercised even when using the plastic analysis method in the methodology combination approved in Appendix F. This is especially important for identifying buckling or instability problems when the change of