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:
C-3511 and ND-3511 for Code Class 2 and 3 valves, respectively. Safe Shutdown Earthquake (SSE). That earthquake which produces the vibratory ground motion for which structures, systems, and components important to safety are designed to remain functional. Seismic Category I. Those structures, systems, and components that are designed to remain functional if the SSE occurs. Standard or Alternative Design Rules for Class 1 Valves. As specified in NB-3512 and NB-3513 of the ASME Boiler and Pressure Vessel Code, Section III. Upset Plant Condition. Those deviations from the normal plant condition which have a high probability of occurrence. NOTES b. full-scale prototype testing. c. reduced-scale prototype testing d. detailed stress and deformation analyses (includes experimental stress and deformation analyses). In the performance of tests or analyses to demonstrate operability, the structural interaction of the entire assembly (e.g., valve-operator assembly and pump-motor assembly) should be considered. If superposition of test results for other than the combined loading condition is proposed, the applicability of such a procedure should be demonstrated. The design limits for non-active pumps and valves designed by analysis may be used for the applicable loading combinations if assurance is provided by detailed stress and deformation analyses that operability is not impaired when designed to these limits. Similarly, the primary-pressure ratings Pr for non-active valves designed by standard or alternative design rules may be used for the applicable loading combinations if appropriate testing demonstrates that operability is not impaired when the valve is so rated. 7Secondary effects (stresses and deformations) should be evaluated for the loading combinations designated by regulatory positions 4.a.(2) and 4.a.(3). Local effects (peak stresses) need not be considered for these loading combinations. Applies to all components (vessels, piping, pumps, and valves) that are