6533b835fe1ef96bd129f4fa
RESEARCH PRODUCT
Neutron Diffraction Study of the in Situ Oxidation of UO2
Gilbert CalvarinGurvan RousseauGianguido BaldinozziLionel DesgrangesJean-claude Niepcesubject
In situKineticsNeutron diffractionchemistry.chemical_element02 engineering and technologyCrystal structure[CHIM.MATE]Chemical Sciences/Material chemistry010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesOxygenIsothermal process0104 chemical sciencesInorganic Chemistrychemistry.chemical_compoundCrystallographychemistry[ CHIM.MATE ] Chemical Sciences/Material chemistryLattice (order)Physical chemistryUranium oxidePhysical and Theoretical Chemistry0210 nano-technologydescription
This paper discusses uranium oxide crystal structure modifications that are observed during the low-temperature oxidation which transforms UO(2) into U(3)O(8). The symmetries and the structural parameters of UO(2), beta-U(4)O(9), beta-U(3)O(7), and U(3)O(8) were determined by refining neutron diffraction patterns on pure single-phase samples. Neutron diffraction patterns were also collected during the in situ oxidation of powder samples at 483 K. The lattice parameters and relative ratios of the four pure phases were measured during the progression of the isothermal oxidation. The transformation of UO(2) into U(3)O(8) involves a complex modification of the oxygen sublattice and the onset of complex superstructures for U(4)O(9) and U(3)O(7), associated with regular stacks of complex defects known as cuboctahedra, which consist of 13 oxygen atoms. The kinetics of the oxidation process are discussed on the basis of the results of the structural analysis.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-07-10 |