Document: NRC Regulatory Guide
Document ID: 10f3c2aa-ada2-4132-8d49-7867458d81a7
Document Type: regulatory_guide
Title: Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components + HISTORY - HISTORY 10/2006 – DG-1158 , Proposed Revision 1
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063000278.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.57
CFR Part: 
CFR Title: 

Content:
or which the containment vessel or portions thereof might be designed for during the expected life of the plant. Such loads include design pressure, design temperature, and the design mechanical loads generated by the design basis accident. In this case, the loading combination includes: D + L + Pa + Ta + Ra 1.2.3 Service Conditions The load combinations in these cases correspond to and include Level A service limits, Level B service limits, Level C service limits, Level D service limits and the post-flooding condition. The loads may be combined by their actual time history of occurrence, taking into consideration their dynamic effect upon the structure. DG-1158, Page 7 1.2.3.1 Level A Service Limits These service limits are applicable to the service loadings to which the containment is subjected, including the plant or system design-basis accident conditions for which the containment function is required, excepting only those categorized as Level B, C, or D, or Testing Loadings. The loading combinations corresponding to these limits include the following: (1) Normal operating plant condition D + L + To + Ro + Po (2) Operating plant condition in conjunction with multiple SRV actuations D + L + Ts + Rs + Ps (3) Loss-of-coolant accident D + L + Ta + Ra + Pa (4) Multiple SRV actuations in combination with a small- or intermediate-break accident D + L + Ta + Ra + Pa + Ts + Rs + Ps (5) Normal operating plant conditions in combination with inadvertent full actuation of a post-accident inerting hydrogen control system D + L + To + Ro + Po + Pg3 (6) Pressure test load to ensure that the containment will safely withstand the pressure calculated to result from carbon-dioxide inerting D + 1.10 x Pg3 1.2.3.2 Level B Service Limits These service limits include the loads subject to Level A service limits, plus the additional loads resulting from natural phenomena during which the plant must remain operational. The loading combinations corresponding to these limits include the