Local structure in solid solutions of stabilised zirconia with actinide dioxides (UO{sub 2}, NpO{sub 2})

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.02.014· OSTI ID:21494257

Walter, Marcus ^[1]; Somers, Joseph; Bouexiere, Daniel ^[1]; Rothe, Joerg ^[2]

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

The local structure of (Zr,Lu,U)O{sub 2-x} and (Zr,Y,Np)O{sub 2-x} solid solutions has been investigated by extended X-ray absorption fine structure (EXAFS). Samples were prepared by mixing reactive (Zr,Lu)O{sub 2-x} and (Zr,Y)O{sub 2-x} precursor materials with the actinide oxide powders, respectively. Sintering at 1600 {sup o}C in Ar/H{sub 2} yields a fluorite structure with U(IV) and Np(IV). As typical for stabilised zirconia the metal-oxygen and metal-metal distances are characteristic for the different metal ions. The bond lengths increase with actinide concentration, whereas highest adaptation to the bulk stabilised zirconia structure was observed for U---O and Np---O bonds. The Zr---O bond shows only a slight increase from 2.14 A at 6 mol% actinide to 2.18 A at infinite dilution in UO{sub 2} and NpO{sub 2}. The short interatomic distance between Zr and the surrounding oxygen and metal atoms indicate a low relaxation of Zr with respect to the bulk structure, i.e. a strong Pauling behaviour. -- Graphical abstract: Metal-oxygen bond distances in (Zr,Lu,U)O{sub 2-x} solid solutions with different oxygen vacancy concentrations (Lu/Zr=1 and Lu/Zr=0.5). Display Omitted Research Highlights: {yields} EXAFS indicates high U and Np adaption to the bulk structure of stabilised zirconia. {yields} Zr---O bond length is 2.18 A at infinite Zr dilution in UO{sub 2} and NpO{sub 2}. {yields} Low relaxation (strong Pauling behaviour) of Zr explains its low solubility in UO{sub 2}.

• OSTI ID: 21494257
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 4; Other Information: DOI: 10.1016/j.jssc.2011.02.014; PII: S0022-4596(11)00068-5; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
FINE STRUCTURE
HYDROGEN
INTERATOMIC DISTANCES
NEPTUNIUM
NEPTUNIUM OXIDES
NUCLEAR FUELS
SINTERING
SOLID SOLUTIONS
TEMPERATURE RANGE 1000-4000 K
TRANSMUTATION
URANIUM DIOXIDE
VACANCIES
X-RAY SPECTROSCOPY
ZIRCONIUM OXIDES
ACTINIDE COMPOUNDS
ACTINIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISPERSIONS
DISTANCE
ELEMENTS
ENERGY SOURCES
FABRICATION
FUELS
HOMOGENEOUS MIXTURES
MATERIALS
METALS
MIXTURES
NEPTUNIUM COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
REACTOR MATERIALS
SOLUTIONS
SPECTROSCOPY
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
TRANSURANIUM COMPOUNDS
TRANSURANIUM ELEMENTS
URANIUM COMPOUNDS
URANIUM OXIDES
ZIRCONIUM COMPOUNDS