Local atomic structure of a zirconia-based americium transmutation fuel

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.08.008· OSTI ID:21043735

Walter, Marcus ^[1]; Naestren, Catharina ^[1]; Somers, Joseph ^[1]; Jardin, Regis ^[1]; Denecke, Melissa A; Brendebach, Boris ^[2]

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1. European Commission, Joint Research Centre, Institute for Transuranium Elements, PO. Box 2340, D-76125 Karlsruhe (Germany)
2. Forschungszentrum Karlsruhe, Institut fuer Nukleare Entsorgung (INE), PO. Box 3640, D-76021 Karlsruhe (Germany)

(Zr,Y,Am)O{sub 2} with 6 and 19 mol% Am were prepared by infiltration of americium in porous yttria-stabilised zirconia (YSZ) beads. Samples were sintered at 1600 deg. C in Ar/H{sub 2} to yield Am(III). By annealing them at 1000 deg. C in flowing air, the Am is oxidised to Am(IV). Both Am(III) and Am(IV) samples exhibit the presence of a single (Zr,Y,Am)O{sub 2} phase with fluorite structure. The local atomic structure around the Zr, Y, and Am atoms is determined by EXAFS analysis. The Zr-O bond distance decreases from 2.15 to 2.12 A with increasing Am(III) content, whereas the Y-O bond distance is independent of Am content and oxidation state. The Am(III)-O bond distance is 2.37 A for both Am concentrations, while oxidation to Am(IV) decreases the Am(IV)-O distance to 2.28 A, with a simultaneous expansion of the environment around the Zr atoms. The Am-O bond distances are contracted compared with the compounds Am{sub 2}Zr{sub 2}O{sub 7} and AmO{sub 2} and the distances expected from the ionic radii. - Graphical abstract: Local atomic structure in (Zr,Y,Am(III))O{sub 2-x}. The oxygen vacancies induced by Y and Am(III) dopant ions are associated with Zr atoms. Oxidation in air at 1000 deg. C contracts the Am(IV)-O bond, whereas the Zr environment relaxes.

• OSTI ID: 21043735
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AMERICIUM
AMERICIUM OXIDES
ANNEALING
BOND LENGTHS
FINE STRUCTURE
NUCLEAR FUELS
OXIDATION
POROUS MATERIALS
TEMPERATURE RANGE 1000-4000 K
TRANSMUTATION
VACANCIES
X-RAY SPECTROSCOPY
YTTRIUM OXIDES
ZIRCONIUM OXIDES