Document: NUREG-0800
Document ID: 5cdeed4a-6cd5-4840-90c0-5159fbf2c9f0
Document Type: srp
Title: CHILLED WATER
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1409/ML14093A350.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.2.7
CFR Part: 
CFR Title: 

Content:
ons are designed to seismic Category II 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. RTNSS C: may apply for defense-in-depth functions in order to meet NRC safety goal guidelines. Replace paragraph 5.B with the following: Important chilled water system portions may be designed against the effects of seismic events. System design bases and criteria and the component classification tables are reviewed for whether the heat exchangers, pumps, valves, and piping of important system portions may be designed to seismic requirements in accordance with the applicable criteria. The review of seismic design and quality group classification is as indicated in Subsection I of this SRP section. Note: RTNSS B SSCs are designed to withstand the effects of natural phenomena without loss of function. RTNSS C SSCs are evaluated, utilizing the “graded approach philosophy,” against the effects of the most probable hazards (e.g., floods, winds, missiles, seismic events). As a result of this evaluation, RTNSS C may be designed against the effects of natural phenomena. SRP Section 19.3 provides further guidance related to the reliability and availability missions of RTNSS B and C SSCs. C. The system is designed to provide water makeup as necessary. Closed-loop VWSs are reviewed for whether the surge tanks (also referred to as expansion tanks) have sufficient capacity to accommodate expected leakage from the system 9.2.7-19 Draft Revision 0 – July 2014 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