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Title: Structural study of (N{sub 2}H{sub 5},H){sub 2.9}U{sub 1.1}Ce{sub 0.9}(C{sub 2}O{sub 4}){sub 5}·10H{sub 2}O from a conventional X-ray diffraction diagram obtained on a powder synthesized by a fast vortex process

In the context of research on U/minor actinides for nuclear fuel reprocessing in the transmutation process, developments are first studied with surrogates containing uranium and lanthanides to facilitate testing. The tests consist of precipitating and calcining a hydrazinium uranium/cerium oxalate. The structure of this oxalate had not been previously determined, but was necessary to validate the physicochemical mechanisms involved. The present study, firstly demonstrates the structural similarity of the U/Ce oxalate phase (N{sub 2}H{sub 5},H){sub 2.9}U{sub 1.1}Ce{sub 0.9}(C{sub 2}O{sub 4}){sub 5}·10H{sub 2}O, synthesized using a vortex precipitator for continuous synthesis of actinide oxalates, with previously known oxalates, crystallizing in P6{sub 3}/mmc symmetry, obtained by more classical methods. This fast precipitation process induces massive nucleation of fine powders. Their structural and microstructural determination confirms that the raw and dried phases belong to the same structural family as (NH{sub 4}){sub 2}U{sub 2}(C{sub 2}O{sub 4}){sub 5}·0.7H{sub 2}O whose structure was described by Chapelet-Arab in P6{sub 3}/mmc symmetry, using single crystal data. However, they present an extended disorder inside the tunnels of the structure, even after drying at 100 °C, between water and hydrazinium ions. This disorder is directly related to the fast vortex method. This structure determination can be used as a basismore » for further semi-quantitative analysis on the U/minor actinides products formed under various experimental conditions. - Highlights: • Uranium cerium oxalate precipitate characterization by X-ray powder diffraction. • Morphology characterization by SEM analysis. • Structure determination by unit cell Rietveld refinement.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4]
  1. CEA, DEN, DTEC, SGCS, LMAC, Marcoule, 30207 Bagnols sur Cèze (France)
  2. Centre Européen de la Céramique, SPCTS, UMR-CNRS 7315, Université de Limoges, Faculté des Sciences, 12 rue Atlantis, 87068 Limoges (France)
  3. CEA, DEN, DTEC, SGCS, LGCI, Marcoule, 30207 Bagnols sur Cèze (France)
  4. CEA, DEN, DRCP, SCPS, LC2A, Marcoule, 30207 Bagnols sur Cèze (France)
Publication Date:
OSTI Identifier:
22443492
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 221; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CERIUM; CRYSTAL GROWTH; HCP LATTICES; IONS; MICROSTRUCTURE; MONOCRYSTALS; NUCLEAR FUELS; NUCLEATION; OXALATES; POWDERS; REPROCESSING; SCANNING ELECTRON MICROSCOPY; SYNTHESIS; TRANSMUTATION; URANIUM; X-RAY DIFFRACTION