Document: NRC Regulatory Guide
Document ID: c7b1689b-ff17-4083-9fb1-f91b6965ea1a
Document Type: regulatory_guide
Title: Design Basis Floods for Nuclear Power Plants + HISTORY - HISTORY 02/2022 – DG-1290 , Proposed Revision 3 09/2014 – Periodic Review of Revision 2 – Revise 07/1980 – Errata to Revision 2 07/2024 – DG-1290 Revision 1 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740388.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.59
CFR Part: 
CFR Title: 

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estimating, with an acceptable degree of conser vatism, flood levels on streams resulting from hydrometeorological conditions. For estimating seismically induced flood levels, an acceptable degree of conservatism for evaluating the effects of the in itiating event is provided by Appendix A to 10 CFR Part 100. The conditions resulting from the worst site-related flood probable at the nuclear power plant (e.g., PMF, seismically induced flood, seiche, surge, severe local precipitation) with attendant wind-generated wave activity constitute the design basis flood conditions that safety-related structures, systems, and compo nents identified in Regulatory Guide 1.291 should be 'Corps of Engineers' Probable Maximum Flood definition appears in many publications of that agency such as Engineering Circular EC 1110-2-27, Change 1, "Engineering and Design-Policies and Procedures Pertaining to Determination of Spillway Capacities and Freeboard Allowances for Dams," dated 19 Feb. 1968. The Probable Maximum Flood is also directly analogous to the Corps of Engineers' "Spillway Design Flood" as used for dams whose failures would result in a significant loss of life and property. 'Reguiatory Guide 1.29, "Seismic Design Classification," identifies structures, systems, and components of light-water cooled nuclear power plants that shouild be designed to withstand the effects of the Safe Shutdown Earthquake and remain func tional. These structures, systems, and components are those neces sary to ensure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the reactor and maintain it in a safe shutdown condition, or (3) the capability to prevent or mitfgiate the consequences of accidents that could result in poten tial offsite exposures comparable to the guideline exposures of 10 CFR Part 100. These same structures, systems, and components should also be designed to withstand conditions resulting from the design basis flood and retain capability