DIFFERENTIAL THERMAL ANALYSIS OF THE URANIUM OXIDES

Technical Report · Mon Jan 01 04:00:00 EST 1951

OSTI ID:4313667

Murray, P; Thackray, R W

Characteristic exothermic peaks related to the chemical and phase changes occurring on oxidation of UO/sub 2/ are obtained by differential thermal analysis. From these curves, quantitative estimation of UO/sub 2/ in oxide mixtures is possible. The shapes of the peaks confirm the conclusions of Anderson and Alberman that the initial oxidation from UO/sub 2/ to UO/sub 2.3/ is diffusioncontrolled, whereas nucleation via the breakdown of UO/sub 2.3/ into UO/ sub 2/ and U/sub 3/O/sub 9/ is the rate determining step in the main oxidation to U/sub 3/O/sib 8/. It is suggested that the large volume change arising from the breakdown of UO/sub 2.3/results in the disruption of the matrix and the exposure of fresh surfaces, thus allowing wing rapid oxidation of the UO/sub 2/ to U/sub 3/ OP/sub 8/. It is found that non-stoichiometric oxides in the range UO/sub 2/-U/ sub 3/O/sub 8/ are more susceptible to oxidation than Mallinckrodt UO/sub 2/. This is attributed to the presence of spatial imperfections or lattice defects arising from the interstitial incorporation into the lattice of oxygen atoms in excess of the stoichiometric composition UO/sub 2/. (auth)

• Research Organization: Gt. Brit. Atomic Energy Research Establishment, Harwell, Berks, England
• NSA Number: NSA-12-013068
• OSTI ID: 4313667
• Report Number(s): AERE-M/R-632
• Country of Publication: United Kingdom
• Language: English

Related Subjects

ATOMS
CHEMISTRY
CRYSTALS
DEFECTS
DIFFUSION
EXPANSION
GRAIN BOUNDARIES
INTERSTITIAL ATOMS
LATTICES
MIXING
NUCLEI
OXIDATION
OXIDES
OXYGEN
PHASE DIAGRAMS
REACTION KINETICS
SURFACES
THERMAL ANALYSIS
U3O8
URANIUM DIOXIDE
URANIUM OXIDES
URANIUM TRIOXIDE
VARIATIONS
VOLUME