Urania vapor composition at very high temperatures

Journal Article · Tue Feb 01 00:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3533439· OSTI ID:21538076

Pflieger, Rachel ^[1]; Colle, Jean-Yves ^[1]; Iosilevskiy, Igor ^[2]; Sheindlin, Michael ^[1]

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1. Institute for Transuranium Elements, Joint Research Centre, European Commission, P.O. Box 2340, 76125 Karlsruhe (Germany)
2. Joint Institute for High Temperature, Russian Academy of Science, 125412 Moscow (Russian Federation)

Due to the chemically unstable nature of uranium dioxide its vapor composition at very high temperatures is, presently, not sufficiently studied though more experimental knowledge is needed for risk assessment of nuclear reactors. We used laser vaporization coupled to mass spectrometry of the produced vapor to study urania vapor composition at temperatures in the vicinity of its melting point and higher. The very good agreement between measured melting and freezing temperatures and between partial pressures measured on the temperature increase and decrease indicated that the change in stoichiometry during laser heating was very limited. The evolutions with temperature (in the range 2800-3400 K) of the partial pressures of the main vapor species (UO{sub 2}, UO{sub 3}, and UO{sub 2}{sup +}) were compared with theoretically predicted evolutions for equilibrium noncongruent gas-liquid and gas-solid phase coexistences and showed very good agreement. The measured main relative partial pressure ratios around 3300 K all agree with calculated values for total equilibrium between condensed and vapor phases. It is the first time the three main partial pressure ratios above stoichiometric liquid urania have been measured at the same temperature under conditions close to equilibrium noncongruent gas-liquid phase coexistence.

• OSTI ID: 21538076
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 3; Other Information: DOI: 10.1063/1.3533439; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMICAL ANALYSIS
EQUILIBRIUM
EVAPORATION
FREEZING
LASER-RADIATION HEATING
LIQUIDS
MASS
MASS SPECTROSCOPY
MELTING
MELTING POINTS
PARTIAL PRESSURE
SOLIDS
STOICHIOMETRY
TEMPERATURE RANGE 1000-4000 K
URANIUM DIOXIDE
URANIUM TRIOXIDE
ACTINIDE COMPOUNDS
CHALCOGENIDES
FLUIDS
HEATING
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLASMA HEATING
SPECTROSCOPY
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
URANIUM COMPOUNDS
URANIUM OXIDES