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:
e of their use (see Figure B.8). Because of the enveloping procedures used in preparing the maps, results from their use are highly conservative. Limitations on the use of these generalized methods of estimating PMFs aretidgntified in Section B.4. These limitations should be considered in detail in assessing the applicability of the methods at specific sites. Applicants for licenses for nuclear facilities at sites on nontidal streams in the contiguous United States have the option of using these methods in lieu of the more precise but laborious methods of Appendix A. The results of application of the methods in this ap pendix will in many cases be accepted by the NRC staff with no further verification. 0.2 SCOPE The data and procedures in this appendix apply only to nontidal streams in the contiguous United States. Two procedures are included for nontidal streams east of the 103rd meridian. Future studies are planned to determine the ap plicability of similar generalized methods and to develop such methods, if feasible, for other areas. These studies, to be included in similar appendices, are anticipated for the main stems of large rivers and the United States west of the 103rd meridian, in cluding Hawaii and Alaska. B.3 PROBABLE MAXIMUM FLOOD PEAK DISCHARGE The data presented in this section are as follows: 1. A tabulation of PMF peak discharge determina. tions at specific locations throughout the contiguous United States. These data are subdivided into water resources regions, delineated on Figure B.1, and are tabulated in Table B.1. 2. A set of six maps, Figures B.2 through B.7, covering index drainage areas of 100, 500, 1,000, 5,000, 10,000, and 20,000 square miles, containing isolines of equal PMF peak discharge for drainage areas of those sizes east of the 103rd meridian. B.3.1 Use of PMF Discharge Determinations The PMF peak discharge determinations listed in Table B.I are those computed by the Corps of Engineers, by the NRC staff and their consultants, or