Document: NUREG-0800
Document ID: 545a669a-51a1-4b1f-9d90-78ee08ca0845
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070463.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
Detonation Study of Nuclear Reactor Safety Analyses," Sandia National Laboratory, December 1990.53 Zr 2H20 Zr02 2H2 DRAFT Rev. 3 - April 1996 6.2.5-16 APPENDIX A SRP SECTION 6.2.5 DESCRIPTION OF COGAP NOTE: In view of the fact that the COGAP program has been written in inch-pound units, Appendix A and the Metrication Documentation was written with inch-pound units first followed by SI units. The SI units are provided for information only, and are not to be used in executing the COGAP program.54 INTRODUCTION A digital computer program, COGAP (Combustible Gas Analyzer Program), has been developed by the Containment Systems Branch to provide in-house capability for determining hydrogen-oxygen concentrations within reactor containments following loss-of-coolant accidents (LOCAs). The program can also evaluate the 55 performance of a number of combustible control systems. They are the containment atmosphere dilution system (CAD), the recombiner system, and the backup purge system. DISCUSSION In the event of a loss-of-coolant accident(LOCA), hydrogen and oxygen gases will be generated within the reactor containment by several reactions. They are: 1. Metal-water reaction involving the zirconium fuel cladding and the reactor coolant, producing free hydrogen. 2. Radiolytic decomposition of the post-accident emergency cooling solutions, producing both oxygen and hydrogen. 3. Aluminum corrosion by water solutions, producing hydrogen. 4. Zinc corrosion by water solutions, producing hydrogen. If a sufficient amount of hydrogen is generated, it may react with the O present in the containment atmosphere or, in the case of inerted containments, with the oxygen generated following a LOCA. The extent of zirconium-water reaction and associated hydrogen production depends strongly upon the course of events assumed for the accident. Analytically the reaction can be described by: 1lb(0.4536kg)Zr 0.043956lb(0.019938kg)H2 1lb(0.4536kg)Zr 0.021978lb mole(0.009969kg mole)H2 V MRT P V