JRP CALL information
Supported By

European Commission

Short description of the work
During the weeks spent at the JRC-ITU facility, uranium-americium mixed dioxides with Am/(U+Am) ratio equal to 15%, 30% and 50% (at.%) were observed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM) in order to have information both on the surface morphology and on the nanometric structure of the grains.
In the TEM, electron energy loss spectroscopy (EELS) measurements were performed. In particular, EELS-spectra were collected on the Oxygen-K edge. Two main intense peaks due to O2p-5f and O2p-6d hybridization bands are observed with different resonances up to 570 eV due to multi-scattering (MS) contributions of successive coordination shells around oxygen atoms within the fluorite structure (typical of actinide dioxides). Both peaks and MS features are very sensitive to symmetry change and can be used to obtain information on the anion sub-lattice.
These data will be completed with XANES and EXAFS measurements on the same samples which will provide complementary information on the uranium-americium sublattice.
Analysis of the acquired data will now be performed jointly by ITU and CEA.

Main visitor contact data
Name: Enrica Epifano
Organisation: CEA

JRP Identification
JRP nr: TALI-C05-14
JRP title: Determination of O/(U+Am) ratios, charge distribution and local structure in uranium-americium mixed oxides using XAS and EELS measurements
JRP scope: Scope 3: Actinide materials

Visited Associated Pooled Facility
Visited APF during the stay: JRC-ITU - Labs & Hot-cells
Name of the APF Contact Person: Thierry Wiss

Other APF and organisation involved in the JRP
Other organisations involved:
Other APF involved in the project: HZDR - ROBL

Description of the work done at the associated pooled facility
Start date of the stay: 11/19/2015
End date of the stay: 11/24/2015
Quantity of access: 22
Access Unit: Days
Misc.: Work during week-ends