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:
ope with the effects of specified plant conditions. Loading combinations are defined as those loadings or combinations thereof-that are associated with each plant condition or specified seismic event. These loadings result from'the various transients or events that are included within each plant condition and the magnitude of the specified seismic events associated with the nuclear power plant site. Identification of the particular transients or events to be evaluated for each plant condition will be addressed in a future guide; however, only the most adversejloadings resulting from those transients or events associated with each plant condition and specified seismic event as combined herein should be considered for design (e.g., those combinations of loadings that result in the limiting or controlling design condition). The combinations of loadings are based upon information contained in recent applications for construction permits, the anticipated sequence of' occurrences which produ'ce loadings, and the most limiting combination of low-probability postulated accidents or events (i.e., the concurrent loadings associated with the normal plant condition, the vibratory motion of the SSE, and the dynamic system loadings associated with the faulted plant condition). Although the loadings associated with each plant condition and specified seismic event delineated in this guide are combined in the same maniner for all classes of components, the design limits 'and specific loadings associated with each plant condition-are not the same for all classes of components (e.g., the dynamic loadings associated with the faulted plant condition may not be present for all Code Class 2 and 3 components because piping ruptures may be postulated to occur only- for certain Code Class 2 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