Effects of lateral separation of oxidic and metallic core debris on the BWR (Boiling Water Reactor) MK I containment drywell floor
In evaluating core debris/concrete interactions for a BWR MK I containment design, it has been common practice to assume that at reactor vessel breach, the core debris is homogeneous and of low viscosity so that it is uniformly distributed radially on the drywell floor. In a recent study performed by the NRC-sponsored Severe Accident Sequence Analysis (SASA) program at Oak Ridge National Laboratory, calculations indicate that at reactor vessel bottom head failure, the debris temperature is such that the metallic components (Zr, Fe, Ni, Cr) are completely molten while the oxidic components (UO/sub 2/, ZrO/sub 2/, FeO) are completely frozen. Thus, the frozen oxides are expected to remain within the reactor pedestal while the molten metallic species radially separate from the frozen oxidic species, flow through the opening in the reactor pedestal, and spread over the annular region of the drywell floor between the pedestal and the containment shell. This report assesses the impact on calculated debris gas release and the production and release of fission product-laden aerosols for two different cases of debris distribution: uniform distribution, and the laterally separated case of 95% oxides-5% metals inside the pedestal and 5% oxides-95% metals outside the pedestal. The computer codes used in this assessment are CORCON-MOD 2, MARCON 2.1B and VANESA.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Nuclear Regulatory Commission, Washington, DC (USA). Office of Nuclear Regulatory Research
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6658826
- Report Number(s):
- NUREG/CR-4610; ORNL/TM-10057; ON: TI87005234
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of lateral separation of oxidic and metallic core debris on the BWR MK I containment drywell floor
Impact of core-concrete interactions in the Mark I containment drywell on containment integrity and failure of the drywell liner
Related Subjects
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BWR TYPE REACTORS
CONTAINMENT SYSTEMS
REACTOR CORE DISRUPTION
CORIUM
RADIOACTIVE EFFLUENTS
AFTER-HEAT REMOVAL
COMPUTER CALCULATIONS
CONCRETES
HEAT TRANSFER
HYDRAULICS
LAYERS
MELTDOWN
METALS
OXIDE MINERALS
REACTOR CORES
REACTOR MATERIALS
REACTOR SAFETY
REACTOR VESSELS
ACCIDENTS
BUILDING MATERIALS
CONTAINERS
CONTAINMENT
ELEMENTS
ENERGY TRANSFER
ENGINEERED SAFETY SYSTEMS
FLUID MECHANICS
MATERIALS
MECHANICS
MINERALS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
REACTOR ACCIDENTS
REACTOR COMPONENTS
REACTORS
REMOVAL
SAFETY
WASTES
WATER COOLED REACTORS
WATER MODERATED REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety
210100 - Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled