United States Nuclear Regulatory Commission - Protecting People and the Environment

Hydrogen-Air-Diluent Detonation Study for Nuclear Reactor Safety Analyses (NUREG/CR-5525, SAND89-2398)

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Publication Information

Manuscript Completed: December 1990
Date Published:
January 1991

Prepared by:
Douglas W. Stamps, William B. Benedick, Sheldon R. Tieszen
Reactor Safety Research Department
Severe Accident Containment Response Division
Sandia National Laboratories
P.O. Box 5800
Albuquerque, New Mexico 87185-5800
Operated by Sandia Corporation

Prepared for:
Division of Systems Research
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

NRC FIN A-1246

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The detonability of hydrogen-air-diluent mixtures was investigated experimentally in the 0.43 m diameter, 13.1 m long Heated Detonation Tube HDT) for the effects of variations in hydrogen and diluent concentration, initial pressure, and initial temperature. The data were correlated using a ZND chemical kinetics model. The detonation limits in the HDT were obtained experimentally for lean and rich hydrogen-air mixtures and stoichiometric hydrogen-air-steam mixtures.

The addition of a diluent, such as steam or carbon dioxide, increases the detonation cell width for all mixtures. In general, an increase in the initial pressure or temperature produces a decrease in the cell width. In the HDT, the detonable range of hydrogen in a hydrogen-air mixture initially at 1 atm pressure is between 11.6 percent and 74.9 percent for mixtures at 20 °C, and 9.4 percent and 76.9 percent for mixtures at 100 °C. The detonation limit is between 38.8 percent and 40.5 percent steam for a stoichiometric hydrogen-air-steam mixture initially at 100 °C and 1 atm. The detonation limit is between 29.6 percent and 31.9 percent steam for a stoichiometric hydrogen-air-steam mixture for the case where hydrogen and steam are added to air initially at 20 °C and 1 atm resulting in a final predetonation mixture temperature and pressure of approximately 100°C and 2.6 atm, respectively.

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