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:
y 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 relied upon to cope with the effects of specified plant conditions. 2Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code including the 1972 Winter Addenda thereto. 'Identification of the specific transients or events to be considered under each plant condition will be addressed in a future regulatory guide. 4 The requirements of the Case 1552 (Interpretations of ASME Boiler and Pressure Vessel Code) should be met for all sizes of Code Class 1 valves designed by analysis. 'The provisions of NB-3411 and NB-3413 may be applied for all sizes of Code Class 1 pumps designed by analysis. 6'Inaddition to compliance with the design limits specified, assurance of operability under all design loading combinations should be provided by an appropriate combination of the following suggested measures: a. in situ testing (e.g., preoperational testing after the component is installed in the plant). 1.48-7 I 8Table 1-3.0, "Permanent Strain Limiting Factors," of Appendix I of the ASME Boiler and Pressure Vessel Code, Section III, may be used as an aid in determining the relationship between design stress and deformation (see note 2 to Table 1-1.2, of Sectiori Ill of the ASME Code). 9 Division 1 of Section VIII of the ASME Boiler and Pressure Vessel Code does not provide rules for design by analysis. If a detailed analysis is performed, Division 1 vessels should meet, as a minimum, equations a and b below. which arc applicable to regulatory positions 6.a. and 6.b., respectively. a. om < 1.IS > m +Ob 1.5 b. am < 1.5S > Om +o b in 1.5 where: urn = primary membrane stress; ob = primary bending stress; S = allowable stress value as specified in Appendix I of Section III of the ASME Boiler and Pressure Vessel Code. " For the loadings designated in