Document: NRC Regulatory Guide
Document ID: 111e064c-2d28-4647-872a-806b29019408
Document Type: regulatory_guide
Title: Design Limit and Loading Combinations for Seismic Category I Fluid System Components
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1229/ML12298A124.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.48
CFR Part: 
CFR Title: 

Content:
May 1973 U.S. ATOMIC ENERGY COMMISSION R~ GULATO GiE DIRECTORATE OF REGULATORY STANDARDS, REGULATORY GUIDE 1.48 DESIGN LIMITS AND LOADING COMBINATIONS FOR SEISMIC CATEGORY I FLUID SYSTEM COMPONENTS A. INTRODUCTION General Design Criterion 2, "Design Bases for Protection Against Natural Phenomena," of Appendix A to 10 CFR Part 50, "General Design Criteria for Nuclear Power Plants," requires, in part, that the design bases for structures, systems, and components important to safety reflect appropriate combinations of the effects of normal and accident conditions with the effects of natural phenomena such as earthquakes. This guide delineates acceptable design limits and appropriate combinations of loadings associated with normal operation, postulated accidents, and specified seismic events for the design of Seismic Category I fluid system components (i.e., water- and steam-containing components). This guide applies to light-water-cooled reactors. The Advisory Committee on Reactor Safeguards has been consulted concerning this guide and has concurred in the regulatory position. B. DISCUSSION' The design conditions and functional requirements of fluid system components important to safety in nuclear power, plants should be reflected in the application of appropriate design limits (e.g., stress or strain limits) for the most adverse combination of loadings to which these components may be subjected in service. For components that are constructed in accordance with Section III of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, provision of a design specification which stipulates the design requirements for the component: (i.e., the mechanical and 'operational loadings) and the Code classification of the component (e.g., Code Class 1, 2, or 3) is required. However, neither Section III nor any other published national code or standard provides adequate guidance for selecting code classifications and loading combinations for design or for