Physicochemical Characterization of Capstone Depleted Uranium Aerosols III: Morphologic and Chemical Oxide Analyses
The impact of depleted uranium (DU) penetrators against an armored target causes erosion and fragmentation of the penetrators, the extent of which is dependent on the thickness and material composition of the target. Vigorous oxidation of the DU particles and fragments creates an aerosol of DU oxide particles and DU particle agglomerations combined with target materials. Aerosols from the Capstone DU aerosol study, in which vehicles were perforated by DU penetrators, were evaluated for their oxidation states using X-ray diffraction (XRD) and particle morphologies using scanning electron microscopy/energy dispersive spectrometry (SEM/EDS). The oxidation state of a DU aerosol is important as it offers a clue to its solubility in lung fluids. The XRD analysis showed that the aerosols evaluated were a combination primarily of U3O8 (insoluble) and UO3 (relatively more soluble) phases, though intermediate phases resembling U4O9 and other oxides were prominent in some samples. Analysis of particle residues in the micrometer-size range by SEM/EDS provided microstructural information such as phase composition and distribution, fracture morphology, size distribution, and material homogeneity. Observations from SEM analysis show a wide variability in the shapes of the DU particles. Some of the larger particles appear to have been fractured (perhaps as a result of abrasion and comminution); others were spherical, occasionally with dendritic or lobed surface structures. Amorphous conglomerates containing metals other than uranium were also common, especially with the smallest particle sizes. A few samples seemed to contain small chunks of nearly pure uranium metal, which were verified by EDS to have a higher uranium content exceeding that expected for uranium oxides. Results of the XRD and SEM/EDS analyses were used in other studies described in this issue of The Journal of Health Physics to interpret the results of lung solubility studies and in selecting input parameters for dose assessments.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 951830
- Report Number(s):
- PNNL-SA-49955; HLTPAO; 400403209; TRN: US0902324
- Journal Information:
- Health Physics, 93(3):276-291, Vol. 93, Issue 3; ISSN 0017-9078
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AEROSOLS
COMMINUTION
DEPLETED URANIUM
ELECTRONS
LUNGS
MORPHOLOGY
OXIDATION
OXIDES
PARTICLE SIZE
PENETRATORS
RADIATION PROTECTION
RESIDUES
SOLUBILITY
SPECTROSCOPY
TARGETS
THICKNESS
URANIUM
URANIUM OXIDES
URANIUM OXIDES U3O8
VALENCE
X-RAY DIFFRACTION
depleted uranium
DU
uranium oxidation
X-ray diffraction
XRD
scanning electron microscopy
SEM