Document: NUREG-0800
Document ID: b3542dd9-b995-4eba-aa6c-0f8f08f8c772
Document Type: srp
Title: FLOODS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340525.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.2
CFR Part: 
CFR Title: 

Content:
ction. For SAR Section 2.4.2.3 (Effects of Local Intense Precipitation): The applicant's estimates of local probable maximum precipitation (PMP) and the capacity of site drainage facilities (including drainage from the roofs of buildings and site ponding) are acceptable if the estimates are no more than 5% less conservative than the corresponding staff's assess- ment. Similarly, conclusions relating to the potential for any adverse effects of blockage of site drainage facilities by debris, ice, or snow should be based upon conservative assumptions of storm and vegetation conditions likely to exist during storm periods. If a potential hazard does exist (e.g., the elevation of ponding exceeds the elevation of plant access openings), the applicant should document and justify his local PMP basis and analysis and redesign any affected facilities. Appropriate sections of the following documents are used by the staff to determine the acceptability of the applicant's data and analyses in meeting the requirements of GDC 2 and 10 CFR Part 100. Regulatory Guide 1.59 provides guidance for estimating the design basis for flooding considering the worst single phenomenon and combinations of less severe phenomena. Regulatory Guide 1.29 identifies the safety-related structures, systems, and components, and Regulatory Guide 1.102 describes acceptable flood 2.4.2-3 Rev. 3 - April 1989 protection to prevent the safety-related facilities from being adversely affected. Publications of the U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), Soil Conservation Service (SCS), Corps of Engineers, applicable State and river basin authorities, and other similar agencies are used to verify the applicant's data re- lating to hydrologic characteristics and extreme events in the region. SRP Sections 2.4.3 through 2.4.7 discuss methods of analysis to determine the individual flood-producing phenomena. III. REVIEW PROCEDURES Construction permit (CP) stage reviews