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: 

Content:
duced floods should in clude the same range of seismic events as is postulated for the design of the nuclear plant. For in stance, the analysis of floods caused by dam failures, landslides, or tsunami requires consideration of seismic events of the severity of the Safe Shutdown Earthquake occurring at the location that would produce the worst such flood at the nuclear power plant site. In the case of seismically induced floods along rivers, lakes, and estuaries that may be produced by events less severe than a Safe Shutdown Earthquake, consideration should be given to the coincident occurrence of floods due to severe hydrometeorological conditions, but only where the effects on the plant are worse than and the probability of such combined events may be greater than an individual occurrence of the most severe event of either type. Appendix A contains acceptable combinations of such events. For the specific case of seismically induced floods due to dam failures, an evaluation should be made of flood waves that may be caused by domino-type dam failures triggered by a seismically induced failure of a critically located dam and of flood -waves that may be caused by multiple dam failures in a region where dams may be located close enough together that a single seismic event can cause multiple failures. Each of the severe flood types discussed above should represent the upper limit of all potential phenomenologically caused flood combinations con sidered reasonably possible. Analytical techniques are available and should generally be used for predic "See References 2 and 5, Appendix C. tion at individual sites. Those techniques applicable to PMF and seismically induced flood estimates on streams are presented in Appendices A and B of this guide. For sites on coasts, estuaries, and large lakes, techniques are presented in Appendices A and C of this guide. Analyses of only the most severe flood conditions may not indicate potential threats to safety-related systems that