Document: NUREG-0800
Document ID: be033a97-be2a-4a23-91fe-52b123162b3b
Document Type: srp
Title: LOW WATER CONSIDERATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730439.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.11
CFR Part: 
CFR Title: 

Content:
rologically-related events, availability of sufficient warning time should be demonstrated so that the plant may be shut down during or in advance of adverse events without causing potential damage to safety-related facilities. Effects to the intake structure and pump design basis in relation to the events described in SAR Sections 2.4.7, 2.4.8, 2.4.9, and 2.4.11 are evaluated considering the range of water supply required by the plant (including minimum operating and shutdown flows during anticipated operational occurrences and emergency conditions) and compared to availability of water. This evaluation includes assessment of the capability of the ultimate heat sink to provide adequate cooling water under conditions requiring safety-related cooling. Minimum plant requirements (water level and flow) that are identified in this section (or Section 9.2.5) are compared with the estimated minimum water levels and flows identified in this section. If normal operation is not ensured at the minimum water supply conditions and loss of normal operation capability can adversely affect safety-related components, the estimates of warning time are reviewed to ensure that shutdown or conversion to alternate water sources can be accomplished prior to the trip. For such cases, emergency operating procedures are required and are reviewed to ensure that they are consistent with the postulated conditions. The analysis of the dependability of the ultimate heat sink is reviewed and the conclusions are provided to the SPLB. The dependability of the ultimate heat sink should be reviewed using Regulatory Guide 1.27 as a standard of comparison. The sources of water for normal operations, anticipated operational occurrences, or emergency shutdown and cooldown, and the natural phenomena and site-related accident design criteria for each should be identified. First, a systems analysis is undertaken of all water supply sources to determine the likelihood that at least one source would survive