Document: NUREG-0800
Document ID: eea126bc-3192-4a98-b937-2f09794010cd
Document Type: srp
Title: COOLING WATER SUPPLY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340556.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.11
CFR Part: 
CFR Title: 

Content:
ed water supply. Applicable literature describing historic sediment accumulations in the site region is reviewed to determine if mitigative measures are required to protect safety- related facilities. Independent estimates of "worst-case" buildups will be made using statistical or deterministic techniques. For plants using rivers, minimum design service water levels are compared with asymtotic extrapolations of low-flow frequency curves which have been corrected for historical and potential future effects. For ocean or estuary plants, design low water levels are compared with probable maximum hurricane and tsunami-induced low water levels. For Great Lakes plants, design low water levels are compared with minimum historical levels coincident with probable maximum surge or seiche- induced low water levels. The ability of the ultimate heat sink to provide a 30-day supply of cooling water, as specified in Regulatory Guide. 1.27, will be independently evaluated. For those cases where makeup water cannot be assured (e.g., an onsite cooling pond supplied from a nearby river through nonseismic piping), estimates of water loss due to drift, evaporation, blowdown, and seepage are made. Techniques described in References 24 and 25 are used to evaluate the adequacy of the initial water inventory under meteorological conditions of the severity discussed in Regulatory Guide 1.27. If the ultimate heat sink system is not capable of continued long-term water supply under the criteria in Regulatory Guide 1.27, 6r the above considerations, the system will be reviewed in two parts: short-term capability and long-term capability. For short-term capability, the AEB, PSB, and the Licensing Project *Manager (LPM) will'be informed if the independently-estimated supply appears to be less than 30 days. The applicant will be asked to determine whether sufficient personnel and equipment can safely be made available to switch water supply sources in the event of an accident. If emergency