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:
5 meters [(566.1 feet) above mean sea level]. 71 The lowest lake level observed at B City during the 70 years of record was 172.4 meters (565.7 feet) above International Great Lakes Datum 172.9 meters [(567.2 feet) above 72 73 mean sea level] on February 4, 1936. Recurrence 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 numerical surge model. The minimum calculated lake level, including an antecedent level equal to the minimum monthly lake level of record, is 167.3 meters (549.0 feet) above International Great 74 Lakes Datum 167.8 meters [(550.4 feet) above mean sea level]. Since this level is 75 below the minimum necessary 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 603.5 meters (1980 feet) long and 76 286.5 meters (940 feet) wide. The depth of the water will be 3.4 meters (11 feet) and 77 78 the pond's embankment will have a freeboard of 1.5 meters (5 feet). The submerged 79 intake and discharge pipes will be located at the same end of the pond but separated by a dike running almost the entire length of the pond to prevent short-circuiting between the intake and discharge. The pond must be capable of providing cooling water below the design temperature of 43.3 C (110 F) under normal operation or emergency 80 81 conditions. The applicants analyzed the pond's thermal performance assuming a