Impact of core-concrete interactions in the Mark I containment drywell on containment integrity and failure of the drywell liner
Previous containment analyses of the Mark I BWR have considered the ..gamma..-mode of containment failure as the dominant mode. The ..gamma..-mode is over-pressure failure of the drywell linear resulting in release of fission products and aerosols directly into the reactor building. The failure pressure for this event has been estimated at 132 psia. However, results from the SASA program analyses of the Mark I BWR have indicated that high temperatures in the drywell during ex-vessel core-concrete interactions may result in containment failure due to seal degradation prior to gross failure due to over-pressurization. It has become evident that a third mode of drywell failure must be considered under these specified accident conditions, in addition to the gross over-pressure failure and the leak-before-failure modes. This third mode of failure is local ablation of the steel drywell liner due to contact with the molten corium. In order to assess the drywell liner response to heat transfer from a pool of molten core debris during a core-concrete interaction, a calculational procedure consisting of both code calculations and hand calculations was developed. The general methodology was to calculate the melting attack on the steel liner by molten core debris that is simultaneously attacking the drywell concrete floor. 15 refs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA); Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6476557
- Report Number(s):
- BNL-NUREG-37131; CONF-851019-8; IAEA-SM-281/36; ON: TI86003375
- Resource Relation:
- Conference: International symposium on source term evaluation for accident conditions, Columbus, OH, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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