Overpressure in a CANDU containment due to hydrogen deflagration

Conference · Mon Dec 01 04:00:00 EST 1997

OSTI ID:549129

Wang, L L; Wong, R C ^[1]

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1. Ontario Hydro, Toronto (Canada)

During a severe accident, hydrogen can be released into the containment. If a flammable mixture forms and burns, it may pose a challenge to containment integrity. To prevent damaging burns from occurring, a hydrogen ignition system is installed to deliberately burn the mixture near the flammability limit, before a sensitive mixture can arise. To demonstrate that the installed hydrogen mitigation system will prevent damaging burns, a lumped-parameter burn model is used to calculate the peak pressure rise. This paper presents the results of the overpressure due to hydrogen deflagration in a CANDU containment by means of a structural criterion curve which defines the envelope of non-damaging bums. This curve is used to establish a composition criterion for determining if a particular combustible hydrogen-air-steam composition will result in overpressures that can cause through-wall-cracking of the concrete structures in containment. The lumped-parameter burn model in the GOTHIC computer code was used for the calculations. In the calculations, hydrogen was assumed to be released into one of the six interconnected auxiliary rooms in a CANDU containment. Because of the complex geometry, and because the hydrogen-air-steam mixture is not completely mixed during the time when hydrogen is being released from the break, all six rooms were assumed to have the same uniformly mixed hydrogen-air-steam composition. 8 refs., 3 figs., 1 tab.

• OSTI ID: 549129
• Report Number(s): CONF-970607--Vol.1
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
CANDU TYPE REACTORS
CONTAINMENT SHELLS
G CODES
HYDROGEN
IGNITION
LOSS OF COOLANT
MOLTEN METAL-WATER REACTIONS
PRESSURIZATION