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:
ation 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 VWS system boundaries, VWS pump seal leakage, equipment gaskets, and general valve packing leakage. Long term water surge tank manual makeup should be available post 7 days for up to 30 days from non-seismic category I sources. Surge tanks are to be designed with instrumentation to determine overall system leakage if a safety related seismic category I makeup system is not utilized. Surge tanks are designed for normal system and abnormal in-leakage contractions and expansion without radiological consequences such as spills of VWS to the floor. RTNSS B: applies since RTNSS B SSCs are considered risk-significant. RTNSS C: applies for defense-in-depth functions in order to meet NRC safety goal guidelines. For RTNSS B and RTNSS C, replace paragraph 5.C with the following: The system is designed to provide water makeup as necessary. Closed-loop VWSs are reviewed for whether the surge tanks have sufficient capacity to accommodate expected leakage. Automatic or manual makeup operation may be required. Surge tanks are to be designed with instrumentation to determine overall system leakage. Surge tanks are designed for normal system and abnormal in-leakage contractions and expansion without radiological consequences such as spills of VWS to the floor. D. The system is designed for removal of heat loads during normal operation and for VWS heat loads during accident conditions with the appropriated design margins (including considerations for heat exchanger tube plugging and fouling) for adequate operations. A comparative analysis is made of the