Interaction of uranium dioxide with molten zircaloy

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6835028

Kim, K T

Laboratory experiments in which gram quantities of molten Zircaloy were held in contact with UO/sub 2/ for known times (20-600 s) and temperatures (1900-2200/sup 0/C) were conducted. Following each experiment, polished sections of the specimen were examined by optical microscopy, electron microprobe, scanning Auger microscopy, and x-ray fluorescence spectroscopy. Three closely-related experiments were conducted. In the first, the molten metal was contained in a UO/sub 2/ crucible. The dissolution rate in this system was found to be dominated by natural convection in the melt driven by density gradients established by the dissolving uranium. The mechanism of the interaction also was observed to involve penetration and detachment of the grains of the oxide by the molten metal. Similar tests with single-crystal UO/sub 2/ specimens showed similar dissolution behavior. Less severe attack occurred because of the absence of grain boundaries, although subgrain boundaries or dislocations provided high-diffusivity pathways for preferential oxygen removal. In the third type of test, a disk of UO/sub 2/ was placed at the bottom of a ThO/sub 2/ crucible. This arrangement prevented establishment of unstable density gradients in the liquid phase, resulting in a purely diffusion-controlled interaction.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6835028
• Country of Publication: United States
• Language: English

Related Subjects

050000 -- Nuclear Fuels
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ACTINIDE COMPOUNDS
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
DISSOLUTION
ELEMENTS
FLUIDS
LIQUID METALS
LIQUIDS
METALS
OXIDES
OXYGEN COMPOUNDS
TIN ALLOYS
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES
VERY HIGH TEMPERATURE
ZIRCALOY
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS