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:
stage statement follows: The normal water supply for the station will be obtained from Lake A. Emergency cooling water will be furnished by the ultimate heat sink reservoir which is not dependent upon the water level in Lake A for its safety function. The minumum lake elevation needed for operation of the pumps supply- ing makeup water for the circulating and the service water systems is 564.6 feet above International Great Lakes Datum (566.1 feet above mean sea level). The lowest lake level observed at B City during the 70 years of record was 565.7 feet above International Great Lakes Datum (567.2 feet above mean sea level) on February 4, 1936. Recur- rence of this low lake level would not affect the plant's ability to obtain water. The applicants calculated the probable minimum lake setdown during a postulated probable maximum windstorm using a one-dimension numeri- cal surge model. The minimum calculated lake level, including an antecedent level equal to the minimum monthly lake level of record, is 549.0 feet above International Great Lakes Datum (550.4 feet 2.4.11-6 Rev. 2 - July 1981 above mean sea level). Since this level is.below the minimum neces- sary for pump submergence, the plant would have to be shut down using water from the ultimate heat sink reservoir, which would not be affected by the postulated low lake level. The proposed ultimate heat sink will be comprised of Lake A and a rectangular cooling pond located'on the site. Normal operation and shutdown will utilize cooling water from the natural draft cooling towers; the makeup for the cooling towers comes from Lake A. If, for any reason, the natural draft cooling towers are unavailable, the onsite pond will be used to shut down the units. The pond will be 1980 feet long and 940 feet wide. The depth of the water will be 11 feet and the pond's embankment will have a freeboard of 5 feet. The submerged intake and discharge pipes will be located at the same end of the pond but separated by a dike running