Document: NUREG-0800
Document ID: 2768345e-44b7-48d8-bfa7-69652aa4faa8
Document Type: srp
Title: CONCRETE CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A245.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.1
CFR Part: 
CFR Title: 

Content:
Ra, Rrr, Rrj, and Rrm should be applied simultaneously, where appropriate, unless a time-history analysis is performed to justify doing otherwise. B. Hydrodynamic loads resulting from LOCA and/or SRV actuation should be combined as indicated in the appendix to this SRP section. Fluid-structure interaction associated with these hydrodynamic loads and those from earthquakes should be considered. C. As noted in Appendix S to 10 CFR Part 50, the OBE is only associated with plant shutdown and inspection unless specifically selected by the applicant as a design input. If the OBE is set at one-third or less of the SSE ground motion, an explicit analysis or design is not required. If the OBE is set at a value greater than one- third of the SSE, an analysis and design must be performed to demonstrate that the containment remains functional and is within applicable stress, strain, and deformation limits. SRP Section 3.7 provides further guidance on the use of OBE. When the OBE is defined as less than one-third of the SSE (and therefore the OBE does not need to be considered in design), certain structural elements of the containment (e.g., penetrations or bellows) still need to be evaluated for fatigue resulting from the OBE-induced stress cycles. In these instances, the guidance for determining the number of earthquake cycles for use in fatigue calculations should be the same as the guidance provided in the staff requirements memorandum (SRM) for SECY-93-087 for piping systems. The number of earthquake cycles to consider is two SSE events with 10 maximum stress cycles per event. Alternatively, the number of fractional vibratory cycles equivalent to that of 20 full SSE vibratory cycles may be used (but with an amplitude not less than one-third of the maximum SSE amplitude) when derived in accordance with Appendix D of IEEE Standard 344-1987. D. Where post-LOCA flooding is a design consideration for the plant, the load combination in the ASME Code containing LOCA flooding