Document: NUREG-0800
Document ID: 8ebc2326-697f-4c5e-986b-6686da2507d0
Document Type: srp
Title: MINIMUM CONTAINMENT PRESSURE ANALYSIS FOR EMERGENCY CORE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600405.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.5
CFR Part: 
CFR Title: 

Content:
COOLING SYSTEM PERFORMANCE CAPABILITY STUDIES REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of containment integrity Secondary - None I. AREAS OF REVIEW The specific areas of review are as follows: 1. Following a loss-of-coolant accident in a pressurized water reactor (PWR) plant, the emergency core cooling system (ECCS) supplies water to the reactor vessel to reflood, and thereby cool, the reactor core. The core flooding rate is governed by the capability of ECCS water to displace the steam generated in the reactor vessel during the core reflooding period. For PWR plants, core flooding rate depends directly on containment pressure (i.e., the core flooding rate increases with increasing containment pressure). Therefore, as part of the overall evaluation of ECCS performance, the primary reviewer reviews analyses of the minimum containment pressure possible during the time until the core is reflooded following a loss-of-coolant accident (LOCA) to confirm the validity of the containment pressure in ECCS performance capability studies. The primary reviewer reviews the assumptions for the operation of engineered safety feature heat removal systems, the effectiveness of structural heat sinks within the containment to remove energy from the containment atmosphere, and such other heat removal 6.2.1.5-2 Revision 3 - March 2007 processes as steam in the containment mixing with ECCS water spilling from the break in the reactor coolant system; and in ice condenser containments mixing with water from melted ice that drains into the lower containment volume. The review is for all PWR containment types (i.e., dry, subatmospheric, and ice condenser containments). It should be noted that the minimum containment pressure analysis for ECCS performance evaluation differs from the containment functional performance analysis in that the conservatisms and margins are taken in opposite directions; thus, the minimum containment pressure analysis required by the