JRP CALL information
Supported By

European Commission

Short description of the work
With the help of the TALISMAN project a joint research project was set up, involving the JRC ITU Karlsruhe, TU Delft and the Rossendorf Beamline at the ESRF. The goal was to determine the local structure and oxidation state of uranium‐plutonium mixed dioxide samples laser heated beyond melting. Such research is developed with the more general aim of characterising the behaviour of nuclear materials under extreme conditions, which might be produced, for example, in a nuclear plant mishap.

At the Rossendorf Beamline (ROBL, ESRF, Grenoble) XANES spectra were collected at room temperature in transmission mode at the U LIII and at the Pu LIII edges. Mixed uranum-plutonium dioxides with different composition were compared with spectra of UO2.00, U(IV/V)4O9, U(V/VI)3O8, PuO2 and PuO2-x.

XANES results show that, for a given Pu content, the white lines of the melted and unmelted samples are very similar, indicating that the laser irradiation does not affect significantly the oxygen / metal stoichiometry. In addition, both U and Pu white lines of the MOX samples are well aligned with the UO2 and PuO2 reference compounds, which indicate that both U and Pu mostly remain in their tetravalent oxidation states before and after laser irradiation. The O/M ratios of the melted and unmelted MOX samples remain therefore very close to 2.00.

These results completed the investigation on uranium‐plutonium mixed dioxides together with X-ray diffraction data, electron miscroscopy, Raman spectroscopy and CALPHAD and were published in the Journal of Nuclear Materials: Recent advances in the study of the UO2–PuO2 phase diagram at high temperatures, Journal of Nuclear Materials, Volume 448, Issues 1–3, May 2014, Pages 330-339, http://dx.doi.org/10.1016/j.jnucmat.2014.02.029

Main visitor contact data
Name: Robert Böhler
Organisation: TU Delft

JRP Identification
JRP nr: TALI-C01-04
JRP title: Local structure and oxidation state of uranium‐plutonium mixed dioxide samples laser heated beyond  melting 
JRP scope: Scope 3: Actinide materials

Visited Associated Pooled Facility
Visited APF during the stay: HZDR - ROBL
Name of the APF Contact Person: Andreas Scheinost

Other APF and organisation involved in the JRP
Other organisations involved: TU Delft (Rudy Konings)
Other APF involved in the project: JRC-ITU - Labs & Hot-cells

Description of the work done at the associated pooled facility
Start date of the stay: 10/5/2013
End date of the stay: 10/9/2013
Quantity of access: 4
Access Unit: Days
Misc.: Work during week-ends

Other APF visitors of the JRP during the stay
Visitor 2: Dr Damien Prieur (JRC-ITU)
Visitor 3: Dr Dario Manara (JRC-ITU)
Visitor 4: Mark Sierig
Visitor 5: