Actinide XAS 2014

Actinides in irradiated fuel: A shooting on their capricious redox properties

20 May 2014, 14:55

25m

Festsaal - Plenum (Schloss Böttstein)

Oral Solid State Chemistry and Physics of the Actinides Solid State Chemistry and Physics of the Actinides

Speaker

Claude Degueldre (Paul Scherrer Institut)

Description

Oxide fuels (UOx, MOx) are currently used in the nuclear reactors. The study of the actinides atomic environment in homogeneous non-irradiated/irradiated fuel samples was performed employing x-ray fluorescence (XRF) and x-ray absorption fine structure (XAFS) spectroscopy. This investigation is important from a safety view because the actinides can undergo various redox states going from III to VII in the beginning of the family. Chemical bounds, valences and stoichiometries of the actinides (Th, U, Np, Pu, Am, Cm) are determined from the experimental data gained for the irradiated fuel material examined in its center location and peripheral zone of the fuel as well as when possible for the non-irradiated fuel e.g. [1-6]. Their data are compared with those recorded for AnO2 compounds. The speciation of these actinides in the oxide fuels sample has also been investigated by thermodynamic into account recent chemical data e.g. [7]. The study is completed with recent EELS data e.g. [8,9] offering a zoom in the actinide electronic structures in the dioxide. References [1] C. Cozzo, A. Orlov, C. Borca, C. Degueldre, X-ray absorption in plutonium uranium mixed oxide fuel: Thorium characterization, ,Progress in Nuclear Energy, In Press, Corrected Proof, Available online 2 October 2013 [2] C. Mieszczynski, C. Degueldre, G. Kuri, J. Bertsch, C.N. Borca, Investigation of irradiated uranium-plutonium mixed oxide fuel by synchrotron based micro X-ray diffraction, Progress in Nuclear Energy, Volume 57, May 2012, Pages 130-137 [3] C. Degueldre, C. Cozzo, M. Martin, D. Grolimund, C. Mieszczynski , Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide, Journal of Solid State Chemistry, Volume 202, June 2013, Pages 315-319 [4] C. Degueldre, C. Borca, C. Cozzo, Curium analysis in plutonium uranium mixed oxide by x-ray fluorescence and absorption fine structure spectroscopy, Talanta, Volume 115, 15 October 2013, Pages 986-991 [5] C. Degueldre, M. Martin, G. Kuri, D. Grolimund, C. Borca, Plutonium–uranium mixed oxide characterization by coupling micro-X-ray diffraction and absorption investigations, Journal of Nuclear Materials, Volume 416, Issues 1–2, 1 September 2011, Pages 142-150 [6] C. Degueldre, S. Pin, J. Poonoosamy, D.A. Kulik, Redox state of plutonium in irradiated mixed oxide fuels, Journal of Physics and Chemistry of Solids, Volume 75, Issue 3, March 2014, Pages 358-365 [7] C. Degueldre, R. Schaeublin, J. Krbanjevic, E. Minikus, Electron energy loss spectroscopy investigation through a nano ablated uranium dioxide sample, Talanta, Volume 106, 15 March 2013, Pages 408-413 [8] C. Degueldre, L. Veleva, Electron energy loss spectroscopy investigations through nano-ablated actinide dioxide samples, Progress in Nuclear Energy, In Press, Corrected Proof, Available online 17 December 2013