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Title: High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors

Abstract

Dicesium molybdate (Cs{sub 2}MoO{sub 4})'s thermal expansion and crystal structure have been investigated herein by high temperature X ray diffraction in conjunction with Raman spectroscopy. This first crystal-chemical insight at high temperature is aimed at predicting the thermostructural and thermomechanical behavior of this oxide formed by the accumulation of Cs and Mo fission products at the periphery of nuclear fuel rods in sodium-cooled fast reactors. Within the temperature range of the fuel's rim, Cs{sub 2}MoO{sub 4} becomes hexagonal P6{sub 3}/mmc, with disordered MoO{sub 4} tetrahedra and 2D distribution of Cs–O bonds that makes thermal axial expansion both large (50≤α{sub l}≤70 10{sup −6} °C{sup −1}, 500–800 °C) and highly anisotropic (α{sub c}−α{sub a}=67×10{sup −6} °C{sup −1}, hexagonal form). The difference with the fuel's expansion coefficient is of potential concern with respect to the cohesion of the Cs{sub 2}MoO{sub 4} surface film and the possible release of cesium radionuclides in accidental situations. - Graphical abstract: The weakness of the Cs–O bonds and the disordering of the MoO{sub 4} tetrahedra array in the high-temperature form are responsible for the huge thermal expansion of Cs{sub 2}MoO{sub 4} along the c-axis. - Highlights: • Thermomechanical behavior of Cs{sub 2}MoO{sub 4} fission products compound is studied.more » • High-temperature form of Cs{sub 2}MoO{sub 4} is characterized by XRD and Raman. • Thermal expansion appears very high and anisotropic. • Cohesion between Cs{sub 2}MoO{sub 4} and nuclear fuel seems questionable, and Cs release is expected.« less

Authors:
 [1];  [2];  [2]
  1. Institut de Recherche de Chimie Paris, CNRS—Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris (France)
  2. ICSM–UMR5257 CNRS/CEA/UM2/ENSCM, Site de Marcoule, Bât 426, BP 17171, 30207 Bagnols/Cèze (France)
Publication Date:
OSTI Identifier:
22334286
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 215; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANISOTROPY; CRYSTALS; FAST NEUTRONS; FILMS; FISSION PRODUCTS; HCP LATTICES; MOLYBDATES; RAMAN SPECTROSCOPY; RESONANCE IONIZATION MASS SPECTROSCOPY; THERMAL EXPANSION; X-RAY DIFFRACTION

Citation Formats

Wallez, Gilles, Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, Raison, Philippe E., E-mail: philippe.raison@ec.europa.eu, Smith, Anna L., E-mail: anna.smith@ec.europa.eu, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, Clavier, Nicolas, and Dacheux, Nicolas. High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors. United States: N. p., 2014. Web. doi:10.1016/J.JSSC.2014.04.003.
Wallez, Gilles, Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, Raison, Philippe E., E-mail: philippe.raison@ec.europa.eu, Smith, Anna L., E-mail: anna.smith@ec.europa.eu, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, Clavier, Nicolas, & Dacheux, Nicolas. High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors. United States. https://doi.org/10.1016/J.JSSC.2014.04.003
Wallez, Gilles, Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, Raison, Philippe E., E-mail: philippe.raison@ec.europa.eu, Smith, Anna L., E-mail: anna.smith@ec.europa.eu, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, Clavier, Nicolas, and Dacheux, Nicolas. 2014. "High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors". United States. https://doi.org/10.1016/J.JSSC.2014.04.003.
@article{osti_22334286,
title = {High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors},
author = {Wallez, Gilles and Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris and Raison, Philippe E., E-mail: philippe.raison@ec.europa.eu and Smith, Anna L., E-mail: anna.smith@ec.europa.eu and Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS and Clavier, Nicolas and Dacheux, Nicolas},
abstractNote = {Dicesium molybdate (Cs{sub 2}MoO{sub 4})'s thermal expansion and crystal structure have been investigated herein by high temperature X ray diffraction in conjunction with Raman spectroscopy. This first crystal-chemical insight at high temperature is aimed at predicting the thermostructural and thermomechanical behavior of this oxide formed by the accumulation of Cs and Mo fission products at the periphery of nuclear fuel rods in sodium-cooled fast reactors. Within the temperature range of the fuel's rim, Cs{sub 2}MoO{sub 4} becomes hexagonal P6{sub 3}/mmc, with disordered MoO{sub 4} tetrahedra and 2D distribution of Cs–O bonds that makes thermal axial expansion both large (50≤α{sub l}≤70 10{sup −6} °C{sup −1}, 500–800 °C) and highly anisotropic (α{sub c}−α{sub a}=67×10{sup −6} °C{sup −1}, hexagonal form). The difference with the fuel's expansion coefficient is of potential concern with respect to the cohesion of the Cs{sub 2}MoO{sub 4} surface film and the possible release of cesium radionuclides in accidental situations. - Graphical abstract: The weakness of the Cs–O bonds and the disordering of the MoO{sub 4} tetrahedra array in the high-temperature form are responsible for the huge thermal expansion of Cs{sub 2}MoO{sub 4} along the c-axis. - Highlights: • Thermomechanical behavior of Cs{sub 2}MoO{sub 4} fission products compound is studied. • High-temperature form of Cs{sub 2}MoO{sub 4} is characterized by XRD and Raman. • Thermal expansion appears very high and anisotropic. • Cohesion between Cs{sub 2}MoO{sub 4} and nuclear fuel seems questionable, and Cs release is expected.},
doi = {10.1016/J.JSSC.2014.04.003},
url = {https://www.osti.gov/biblio/22334286}, journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 215,
place = {United States},
year = {Tue Jul 01 00:00:00 EDT 2014},
month = {Tue Jul 01 00:00:00 EDT 2014}
}