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:
and 3 piping). However, a failure in any system or component should be evaluated for its .effects on all other systems and components. ASME Code Class 1 Components Code Class I components, except for pumps and valves, benefit from the most complete design coverage that Section III of the ASME Code provides. Design rules and design limits are available for other than the normal plant condition (e.g., for the severe loadings associated with the emergency and faulted plant conditions and specified seismic events). These severe loadings are accomodated by application of the design limits for the emergency and faulted operating condition categories (as defined in NB-3113 of Section 111) which permit design limits in excess of those allowed for the normal operating condition category. Loadings associated with the normal plant condition and loadings associated with the upset plant condition (i.e., anticipated operational occurrences as defined in Appendix A to 10 CFR Part 50) are sustained by application of the design limits specified for the normal operating condition category and the upset operating condition category of Section III, respectively. ASME Code Class 1 Vessels and Piping To provide assurance of pressure-retaining integrity, the upset, emergency, and faulted operating condition category design limits given in NB-3200, "Design by Analysis," and NB-3600, "Piping Design," of Section III of the ASME Code should be applied to design vessels and piping for the combination of loadings delineated in regulatory positions l.a., 1.b., and l.c., respectively. Non-Active ASME Code Class 1 Pumps and Valves (Designed by Analysis) As permitted by Section III of the ASME Code within the limitations of NB-3400 and NB-32 11, Code Class I pumps may be designed by analysis (i.e., the design procedures specified in NB-3200 of Section III). Case 1552 (Interpretations of ASME Boiler and Pressure Vessel Code) allows design by analysis of Code Class I valves if additional