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:
ts of a trip of the intake pumps is evaluated based on potential surges in intake sumps. For multiple purpose (normal operations, anticipated operational occurrences, normal 46 shutdown, and emergency shutdownand emergency shutdown and cooldown ) water supply 47 systems, the primary portion of the system is first reviewed to determine that the water supply will be maintained at minimum volume requirements at all times. The secondary portion of the system is then reviewed to determine whether an adequate emergency water supply can be expected to be available during operating conditions such as the regional drought of record (flows must be adjusted for historical and potential future effects). If not available, the 48 applicant is requested to provide a technical specification requiring plant shutdown at the point where an adequate shutdown water supply is still assuredensured.49 Institutional restraints on water use, such as limitations in water use and discharge permits, are reviewed to assureensure the plant will have an adequate supply and not exceed limitations 50 imposed upon operation. If a conflict is foreseen, the applicant is requested to either obtain a variance or make a design change to accommodate the limitation. The potential for blockage of the intakes by littoral drift, sediment, and/or ice is reviewed to 51 assureensure that the intakes are located and sized to prevent blockage which would preclude 52 use of the safety-related 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 asymptotic extrapolations of low-flow frequency curves which have been corrected for historical and 2.4.11-9 DRAFT Rev. 3 - April 1996 potential