Document: NUREG-0800
Document ID: 42f941d3-4815-4bc5-bf81-f2dab04a7aa7
Document Type: srp
Title: SECONDARY CONTAINMENT FUNCTIONAL DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070459.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.3
CFR Part: 
CFR Title: 

Content:
255 (TREE-1279), "CONTEMPT-LT/028: A Computer Code for Predicting Containment Pressure-Temperature Response to a Loss-of-Coolant Accident," EG&G Idaho, Inc. for the U.S. Nuclear Regulatory Commission, March 1979.71 49. R. J. Wagner and L. L. West, "CONTEMPT-LT Users Manual," Interim Report I- 214-74-12.1, Aerojet Nuclear Company, August 1973. DRAFT Rev. 3 - April 1996 6.2.3-12 BRANCH TECHNICAL POSITION CSB 6-3 (Currently the responsibility of the Containment Systems and Severe Accident Branch - SCSB)72 DETERMINATION OF BYPASS LEAKAGE PATHS IN DUAL CONTAINMENT PLANTS A. BACKGROUND The purpose of this branch position is to provide guidance in the determination of that portion of the primary containment leakage that will not be collected and processed by the secondary containment. Bypass leakage is defined as that leakage from the primary containment which can circumvent the secondary containment boundary and escape directly to the environment, i.e., bypasses the leakage collection and filtration systems of the secondary containment. This leakage component must be considered in the radiological analysis of a loss-of-coolant accident. The secondary containment consists of a structure which completely encloses the primary containment and can be maintained at a pressure lower than atmospheric so that primary containment leakage can be collected or processed before release to the environment. The secondary containment may include an enclosure building which forms an annular volume around the primary containment, the auxiliary building where it completely encloses the primary containment, and other regions of the plant that are provided with leakage collection and filtration systems. Depressurization systems are provided as part of the secondary containment to decrease or maintain the secondary containment volume at a negative pressure. All primary containment leakage may not be collected because (1) direct primary containment leakage can occur while the secondary