Document: NUREG-0800
Document ID: 47be7233-5326-4a7d-a9c5-f3b91d565a72
Document Type: srp
Title: MINIMUM CONTAINMENT PRESSURE ANALYSIS FOR EMERGENCY CORE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070492.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.5
CFR Part: 
CFR Title: 

Content:
ee volume should be determined from the gross containment volume minus the volumes of internal structures such as walls and floors, structural steel, major equipment, and piping. The individual volume calculations should reflect the uncertainty in the component volumes. 6.2.1.5-7 DRAFT Rev. 3 - April 1996 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 will be accepted if it can be shown that the worst conditions regarding a single active failure, stored water temperature, and cooling water temperature 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 resulting from ice melting in an ice condenser containment provides an additional heat sink as the subcooled water mixes with the steam while draining from the ice condenser into the lower containment volume. The effect of the steam-water mixing should be considered in the containment pressure calculations. 3. Passive Heat