Document: NUREG-0800
Document ID: 90078267-41fd-4e45-bc4c-a21ef5ed6dfb
Document Type: srp
Title: Revision 3 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070740442.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
under limiting normal operating conditions should be used. Ice condenser plants should use the maximum containment gas temperature. B. Initial Outside Containment Ambient Conditions. A reasonably low ambient temperature external to the containment should be used. C. Containment Volume. The maximum net free containment volume should be used. This maximum free volume should be determined from the gross containment volume minus the volumes of such internal structures as walls and floors, structural steel, major equipment, and piping. The individual volume calculations should reflect the uncertainty in the component volumes. D. Purge Supply and Exhaust Systems. If purge system operation is proposed during the reactor operating modes of startup, power operation, hot standby, and hot shutdown, the system lines should be assumed to be initially open. 2. Active Heat Sinks A. Spray and Fan Cooling Systems. The operation of all engineered safety feature containment heat removal systems operating at maximum heat removal capacity (i.e., with all containment spray trains operating at maximum flow conditions and all emergency fan cooler units operating) should be assumed. In addition, the minimum temperature of the stored water for the spray cooling system and the cooling water supplied to the fan coolers, based on technical specification limits, should be assumed. Deviations from the foregoing are accepted if the worst conditions for a single active failure, stored water temperature, and cooling water temperature can be shown to have been selected from the standpoint of the overall ECCS model. B. Containment Steam Mixing With Spilled ECCS Water. The spillage of subcooled ECCS water into the containment provides an additional heat sink as the subcooled ECCS water mixes with the steam in the containment. The effect of the steam-water mixing should be considered in the containment pressure calculations. C. Containment Steam Mixing With Water from Ice Melt. The water from ice