Document: NUREG-0800
Document ID: b1bccb14-17b6-422b-93ee-6d4f00b6512b
Document Type: srp
Title: CHILLED WATER SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1510/ML15103A559.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.2.7
CFR Part: 
CFR Title: 

Content:
s reviewed for minimum performance of the isolation valves. The drawings and description are reviewed for whether automatically operated isolation valves separate non-essential portions and components from the essential components. Special consideration is given to redundant interconnected trains for operation of at least one safety-related train by proper isolation in an accident or anticipated operational occurrence. B. Chilled water system portion, including the isolation valves separating seismic Category I portions from the nonseismic, are Quality Group C and seismic Category I. System design bases and criteria and the component classification 9.2.7-16 Revision 0 – September 2015 tables are reviewed for whether the heat exchangers, pumps, valves, and piping of essential system portions are designed to seismic Category I requirements in accordance with the applicable design criteria. The review of seismic design and quality group classification is as indicated in Subsection I of this SRP section. C. The system is designed to provide water makeup as necessary. Closed-loop CWSs are reviewed for whether the surge tanks (also referred to as expansion tanks) have sufficient capacity to accommodate expected leakage from the system for 7 days or whether a safety-related Seismic Category I automatic source of makeup can be made available within a time frame consistent with the surge tank capacity (the time period is initiated at the actuation of the low level alarm). The surge tank and connecting piping are reviewed for whether makeup water can be supplied to either header in a split header system. Redundant surge tanks (one for each header) or a divided surge tank design is acceptable to ensure that in a header rupture, the entire contents of the surge tank are not lost. Surge tank leakage over a 7 day period should include the possibility of valve seat leakage for CWS system boundaries, CWS pump seal leakage, equipment gaskets, and general valve packing leakage.