Document: NUREG-0800
Document ID: aac96014-0cf1-4116-83f5-f791b43a8be8
Document Type: srp
Title: COOLING WATER CANALS AND RESERVOIRS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340550.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.8
CFR Part: 
CFR Title: 

Content:
ndition. For the shutdown condi- tions, the applicant has demonstrated that the two reservoir-A River diversion system constituting the ultimate heat sink would have a water supply available in excess of 30 days in the auxiliary reservoir if water were not available from the main reservoir-auxiliary reservoir-A River diversion facilities. The operation of the sink as a whole will require that the auxiliary reservoir be kept at its normal operating level of elevation 250 feet MSL at all times by pumping water from the main reservoir to make up for water lost to normal evaporation. For the analyses of evaporation under normal plant operation during periods of assumed recurrence of historical droughts, the applicant has used historical flow records for the A River and synthesized flow data for the drainage area contiguous to the reservoir system. For the analysis of evaporation during a more extreme drought than has occurred historically, the applicant has synthesized flows from both the A River and the contiguous drainage areas for what is called a 100-year frequency drought. The staff, in consonance with our consultant (the U.S. Geological Survey), independently developed and analyzed synthesized flows from both drainage areas. We concluded that it is likely that flows from both areas could be substantially less than estimated by the applicant. The applicant is installing a streamflow gage near the plant to determine runoff characteristics from the contiguous drainage which should allow more accurate analysis of the operating capability of the reservoir system prior to plant operation. Inaccuracies in estimation of runoff are considered to be only indirectly safety related since an adequate shutdown and cool- down water supply will be available in the auxiliary reservoir should evaporation and the lack of runoff prevent replenishment of main reser- voir storage above the minimum operating level of elevation 244 feet MSL. V. IMPLEMENTATION The following is intended to