Document: NUREG-0800
Document ID: ebff6c02-bdd3-4751-9e36-9347caf05c8e
Document Type: srp
Title: and 2.4.6 are applicable to low water estimates due to the various phenomena discussed.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070258.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.5
CFR Part: 
CFR Title: 

Content:
, minimum design service water levels are compared with asymptotic extrapolations of low-flow frequency curves which have been corrected for historical and 2.4.11-9 DRAFT Rev. 3 - April 1996 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 assuredensured (e.g., an onsite cooling pond supplied from a nearby river through 53 nonseismic piping), estimates of water loss due to drift, evaporation, blowdown, and seepage are made. Techniques described in NUREG-0693 and NUREG-0733 References 24 and 25 are 54 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, or the above considerations, the system will be reviewed in two parts: short-term capability and long-term capability. For short-term capability,the AEBPERB, PSBSPLB, and the Licensing Project Manager (LPM) will be informed if the 55 56 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 procedures are required to obtain the use of alternate water supplies, the applicant's water supply sources and procedures will be reviewed with AEBPERB, PSBSPLB, and the LPM to determine that there is continuity of 57 58 water supply. The time period