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:
provide uniform requirements for construction, the component supports should, as a minimum, have the same ASME Code classification as that of the supported components. This guide delineates levels of service limits and loading combinations, in addition to supplementary criteria, for ASME Code Class 1 linear-type component supports, as defined by NF-1213 of Section III. This guide does not address snubbers. Subsection NF of Section III permits the use of four methods for the design of Class 1 linear-type component supports: (1) linear-elastic analysis, (2) load rating, (3) experimental stress analysis, and (4) limit analysis. For each method, the ASME Code delineates allowable stress or loading limits for various code levels of service limits, as defined by NF-3113 of Section III, so that these limits can be used in conjunction with the resultant loadings or stresses from the appropriate plant conditions. Because the ASME Code does not specify loading combinations, guidance is required to provide a consistent basis for the design of component supports. Component supports considered in this guide are located within Seismic Category I structures and, therefore, are assumed to be protected against loadings from natural phenomena (or manmade hazards) other than the specified seismic events. Thus, only the specified seismic events need to be considered in combination with loadings associated with plant conditions to develop appropriate loading combinations. Loadings caused by any natural phenomena other than seismic events should be considered on a case-by-case basis. 2 Regulatory Guide 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME Section III,” 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