Speaker
Dr
Stefan Neumeier
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, 52425 Jülich, Germany)
Description
Phosphate ceramics with monazite structure are considered as potential waste forms for the conditioning of specific nuclear waste streams (e.g. minor actinides and plutonium) due to their outstanding properties. In this study, the incorporation of actinides (Cm3+ and Pu3+) into the monazite structure has been investigated combining X-ray diffraction (XRD) as well as X-ray absorption- (XAS) and time-resolved laser fluorescence spectroscopy (TRLFS).
The results demonstrate the incorporation of the actinides on defined lanthanide lattice sites in the monazite ceramics. From TRLFS measurements of Cm-doped (50 ppm) (La,Gd)PO4 solid solutions, a decrease of short-range order for the solid solution compositions was observed in comparison to the end-members. Additionally, XAS investigations on pure-phase La1-xPuxPO4 (x = 0.01 – 0.15) solid solutions verify the incorporation of plutonium in the +III oxidation state in the monazites. The results provide a refined structural insight into mechanisms of actinide incorporation into monazite ceramics and solid solution formation.
Primary author
Dr
Stefan Neumeier
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, 52425 Jülich, Germany)
Co-authors
Mr
Andre Cabriani
(European Commission, Joint Research Centre, 76125 Karlsruhe, Germany)
Dr
Andreas C. Scheinost
(Helmholtz-Zentrum Dresden-Rossendorf, The Rossendorf Beamline, The European Synchrotron Radiation Facility (ESRF), P.O. Box 40220, 38043, Grenoble, France)
Dr
Andreas Wilden
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, 52425 Jülich, Germany)
Dr
André Rossberg
(Helmholtz-Zentrum Dresden-Rossendorf; The Rossendorf Beamline, The European Synchrotron Radiation Facility (ESRF), P.O. Box 40220, 38043, Grenoble, France)
Prof.
Dirk Bosbach
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, Jülich, Germany)
Dr
Joseph Somers
(European Commission, Joint Research Centre, 76125 Karlsruhe, Germany)
Dr
Karin Popa
(European Commission, Joint Research Centre, 76125 Karlsruhe, Germany)
Dr
Nina Huittinen
(Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany)
Dr
Philippe Raison
(European Commission, Joint Research Centre, 76125 Karlsruhe, Germany)
Mrs
Yulia Arinicheva
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, Jülich, Germany)
