SIGNIFICANCE OF PHYSICAL STATE OF STARTING PRECIPITATE IN GROWTH OF URANIUM DIOXIDE PARTICLES
The effects of physical state of starting ammonium diuranate (ADU) precipitate upon growth of resulting UO/sub 2/ particles in heat treatment have been studied by means of optical and electron-optical microscopy and particle size analysis. It was found that ADU precipitate usually consists of agglomerated particles, and that main feature of the agglomeration essentially persists throughout calcination to UO/sub 3/ and subsequent reduction to UO/sub 2/ at comparatively low temperatures. Further high temperature firing of the loose UO/sub 2/ powder in hydrogen causes extensive grain growth due to sintering. It is indeed remarkable that the influence of the physical state of the starting precipitate reaches as far as the later stage of the sintering process at the elevated temperatures, growth of the resulting UO/sub 2/ being profoundly affected accordingly. In order to attain rapid growth and densification of resulting UO/sub 2/, it was found essential to lower the U concentration of initial UO/sub 2/(NO/sub 3/)/sub 2/ solution in ADU precipitation. (auth)
- Research Organization:
- Mitsubishi Metal Mining and Metallurgical Lab., Omiya City, Japan
- NSA Number:
- NSA-18-017806
- OSTI ID:
- 4055839
- Journal Information:
- Journal of Nuclear Materials (Netherlands), Journal Name: Journal of Nuclear Materials (Netherlands) Vol. Vol: 11; ISSN JNUMA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
CHEMISTRY
COMBUSTION
CONFIGURATION
DENSITY
ELECTRON MICROSCOPY
EXPANSION
FABRICATION
FUELS
GASES
GRAIN SIZE
HEAT TREATMENTS
HIGH TEMPERATURE
HYDROGEN
LOSSES
LOW TEMPERATURE
MICROSCOPY
OPERATION
OXIDATION
POWDERS
PRECIPITATION
PREPARATION
QUANTITY RATIO
REACTION KINETICS
REDUCTION
SINTERED MATERIALS
SINTERING
SOLUTIONS
URANATES
URANIUM
URANIUM DIOXIDE
URANIUM TRIOXIDE
URANYL NITRATES
VARIATIONS
WATER