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Title: Characterization of urania vaporization with transpiration coupled thermogravimetry

Determining equilibrium vapor pressures of materials is made easier by transpiration measurements. However, the traditional technique involves condensing the volatiles entrained in a carrier gas outside of the hot measurement zone. One potential problem is deposition en route to a cooled collector. Thermogravimetric analysis (TGA) can be used to measure in situ mass loss due to vaporization and therefore obviate the need to analyze the entire gas train due to premature plating of vapor species. Therefore, a transpiration coupled TGA technique was used to determine equilibrium pressures of UO3 gas over fluorite structure UO2+x and U3O8 at T = (1573 and 1773) K. Moreover, we compared to calculations from models and databases in the open literature. Our study gives clarity to the thermochemical data for UO3 gas and validates the mass loss transpiration method using thermogravimetry for determining equilibrium vapor pressures of non-stoichiometric oxides.
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Chemical Thermodynamics
Additional Journal Information:
Journal Volume: 95; Journal Issue: C; Journal ID: ISSN 0021-9614
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
Country of Publication:
United States
36 MATERIALS SCIENCE; UO2 +/- x; UO3; Uranium; Urania; Volatilization; Oxygen potential; Phase equilibrium; VAPOR-PRESSURE; FUEL
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1396533