Melt propagation in dry core debris beds

Journal Article · Sun Oct 01 04:00:00 EDT 1989 · Nuclear Technology; (USA)

OSTI ID:7146679

Dosanjh, S S ^[1]

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1. Sandia National Labs., Reactor Safety Theoretical Physics, Albuquerque, NM (US)

During severe light water reactor accidents like Three Mile Island Unit 2, the fuel rods can fragment and thus convert the reactor core into a large particle bed. The postdryout meltdown of such debris beds is examined. A two-dimensional model that considers the presence of oxidic (UO{sub 2} and ZrO{sub 2}) as well as metallic (e.g., zirconium) constituents is developed. Key results are that a dense metallic crust is created near the bottom of the bed as molten materials flow downward and freeze; liquid accumulates above the blockage and, if zirconium is present, the pool grows rapidly as molten zirconium dissolved both UO{sub 2} and ZrO{sub 2} particles; if the melt wets the solid, a fraction of the melt flows radially outward under the action of capillary forces and freezes near the radial boundary; in a nonwetting system, all of the melt flows into the bottom of the bed; and when zirconium and iron are in intimate contact and the zirconium metal atomic fraction is > 0.33, these metals can liquefy and flow out of the bed very early in the meltdown sequence.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7146679
• Journal Information: Nuclear Technology; (USA), Journal Name: Nuclear Technology; (USA) Vol. 88:1; ISSN 0029-5450; ISSN NUTYB
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220500 -- Nuclear Reactor Technology-- Environmental Aspects
220900* -- Nuclear Reactor Technology-- Reactor Safety
ACCIDENTS
ACTINIDE COMPOUNDS
CHALCOGENIDES
ELEMENTS
ENRICHED URANIUM REACTORS
ENVIRONMENTAL IMPACTS
ENVIRONMENTAL TRANSPORT
FUEL ELEMENTS
FUEL RODS
IRON
MASS TRANSFER
MELTDOWN
METALS
MOLTEN SALTS
OXIDES
OXYGEN COMPOUNDS
POWER REACTORS
PWR TYPE REACTORS
RADIONUCLIDE MIGRATION
REACTOR ACCIDENTS
REACTOR COMPONENTS
REACTOR CORES
REACTORS
SALTS
THERMAL REACTORS
THREE MILE ISLAND-2 REACTOR
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TWO-DIMENSIONAL CALCULATIONS
URANIUM COMPOUNDS
URANIUM OXIDES
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES