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:
PMF peak discharge at the site from the curve at the appropriate drainage area. B.3.3 Probable Maximum Water Level When the PMF peak discharge has been obtained as outlined in the foregoing sections, the" PMF still water level should be determined. The methods given in Appendix A are acceptable for this purpose. B.3.4 Wind-Wave Effects Wind-wave effects should be superimposed on the PMF stillwater level. Criteria and acceptable methods are given in Appendihx A. BA LIMITATIONS 1. The NRC staff will continue to accept for review detailed PMF analyses that result in less con servative estimates. In addition, previously reviewed and approved detailed PMF analyses at specific sites will continue to be acceptable even though the data and procedures in this appendix result in more con servative estimates. 2 .The PMF estimates obtained as outlined in Sec tions B.3.1 and B.3.2 are peak discharges that should be converted to water level to which appropriate wind-wave effects should be added. 3. If there are one or more reservoirs in the drainage area upstream of the site, seismic and hydrologic dam failure' flood analyses should be made to determine whether such a flood will produce the design basis water level. Criteria and acceptable methods are included in Appendix A. 4. Because of the enveloping procedures used, PMF peak discharges estimated as outlined in Sec tion B.3.2 have a high degree of conservatism. If the PMF so estimated casts doubt on the-suitability of a site, or if protection from a flood of that magnitude would not be physically or economically feasible, consideration should be given to performing a detailed PMF analysis, as outlined in Appendix A. It is likely that such an analysis will result in ap preciably lower PMF levels. 'In this contest, "hydrologic dam failure" muama failure caused by a flood from the drainage area upstream of the dam. 1.59-13 REFERENCES 1. Nunn, Snyder, and Associates, "Probable Max imum Flood and Hurricane Surge Estimates," un