Document: NUREG-0800
Document ID: be033a97-be2a-4a23-91fe-52b123162b3b
Document Type: srp
Title: LOW WATER CONSIDERATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730439.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.11
CFR Part: 
CFR Title: 

Content:
of complying with the relevant NRC requirements identified in Subsection II. 1. Low Water from Drought: The worst drought considered reasonably possible in the region is reviewed along with a complete history of low water conditions at and in the vicinity of the site, including initiating phenomena, locations and durations of these events, and descriptions of hydrometeorological characteristics accompanying these events that are sufficient to establish the history of droughts in the vicinity of the site. The applicable literature describing historical occurrences of low water in the region is reviewed to determine if additional protection should be considered in the design of safety-related facilities. Publications of the United States Geologic Survey (USGS), the U.S. Army Corps of Engineers (USACE), National Oceanic and Atmospheric Administration (NOAA), and other hydrometeorological sources are used to identify the history and potential for low water in the region. For any extreme low water events, historical water flow variations should be quantified using USGS streamflow data, where possible. For essential water supplies the low-flow/low-level design for the primary water supply source should be based on the probable minimum low flow and level resulting from the most severe drought that can reasonably be considered possible for the region. The low flow and level design bases for operation (if different than the design bases for essential water requirements) should be such that shutdowns caused by inadequate water supply will not cause frequent use of emergency systems. In cases where a common source of cooling water for operation and safety is provided, and where operation can affect minimum levels required for safety, the system will be acceptable if technical specifications are provided for shutdown before the ultimate heat sink can be adversely affected. The staff will evaluate the applicant’s evidence as it relates to low water considerations. If the staff