Document: NUREG-0800
Document ID: 1dda396e-398a-4b85-aa13-c5c1dbf82bc2
Document Type: srp
Title: MINIMUM CONTAINMENT PRESSURE ANALYSIS FOR EMERGENCY CORE COOLING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340670.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.5
CFR Part: 
CFR Title: 

Content:
the calculation include the effects of operation of all installed pressure-reducing systems and processes. Therefore, the following branch technical position has been developed to provide guidance in the performance of a minimum containment pressure analysis. The approach described below applies only to the ECCS-related containment pressure evaluation and not to the containment functional capability evaluation for postulated design basis accidents. B. BRANCH TECHNICAL POSITION 1. Input Information for Model a. Initial Containment Internal Conditions The minimum containment gas temperature, minimum containment pressure, and maximum humidity that may be encountered 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 contain- ment 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. 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. 6.2.1.5-4 Rev. 2 - July 1981 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 condi- tions 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