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:
with attendant wind-generated wave activity that may be produced by the worst winds of record and remain functional; c. In addition to the analyses in paragraph 2.b -above, reasonable combinations of less-severe flood conditions are also considered to the extent needed for a consistent level of conservatism; and 'Hardened protction means structural provisions Incorporated in the plant design that will protect safety-related structures, systems, and components from the static and dynamic effects of floods. In addition, each component of the protection must be passive and In place, as it is to be used for flood protection, during normal plant operation. Examples of the types of flood protection. to be provided for nuclear power plants are contained in Regulatory Guide 1.102. sFor sites along streams, this event is characterized by the Corps of Engineers' definition of a Standard Project Flood. Such floods have been found to produce flow rates generally 40 to 60 percent of the PMF. For sites along seashores, this event may be characterized by the Corps of Engineers' definition of a Standard Project Hurricane. For other sites, a comparable level, of risk should be assumed. 1.59-7 d. In addition to paragraph 2.b above, at least those structures, systems, and components necessary fbr cold shutdown and molntenance thereof are designed with hardened protective features to remain functional while withstanding the entire range of flood conditions up to and including the worst site related flood probable (e.g., PMF, seismically in. duced flood, hurricane, surge, seiche, heavy local precipitation) with coincident wind-generated wave action as discussed in Regulatory Position I above. 3. During the economic life of a nuclear power plant, unanticipated changes to the site environs which may adversely affect the flood-producing characteristics of the environs are possible. Examples include construction of a dam upstream or downstream of the plant or, comparably, construc tion of