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Wilke SK, Benmore CJ, Alderman OLG, Sivaraman G, Ruehl MD, Hawthorne KL, Tamalonis A, Andersson DA, Williamson MA, Weber R. Plutonium oxide melt structure and covalency. NATURE MATERIALS 2024:10.1038/s41563-024-01883-3. [PMID: 38671164 DOI: 10.1038/s41563-024-01883-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
Advances in nuclear power reactors include the use of mixed oxide fuel, containing uranium and plutonium oxides. The high-temperature behaviour and structure of PuO2-x above 1,800 K remain largely unexplored, and these conditions must be considered for reactor design and planning for the mitigation of severe accidents. Here, we measure the atomic structure of PuO2-x through the melting transition up to 3,000 ± 50 K using X-ray scattering of aerodynamically levitated and laser-beam-heated samples, with O/Pu ranging from 1.57 to 1.76. Liquid structural models consistent with the X-ray data are developed using machine-learned interatomic potentials and density functional theory. Molten PuO1.76 contains some degree of covalent Pu-O bonding, signalled by the degeneracy of Pu 5f and O 2p orbitals. The liquid is isomorphous with molten CeO1.75, demonstrating the latter as a non-radioactive, non-toxic, structural surrogate when differences in the oxidation potentials of Pu and Ce are accounted for. These characterizations provide essential constraints for modelling pertinent to reactor safety design.
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Affiliation(s)
- Stephen K Wilke
- Materials Development, Inc., Arlington Heights, IL, USA.
- X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA.
| | - Chris J Benmore
- X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Oliver L G Alderman
- ISIS Neutron & Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - Ganesh Sivaraman
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Matthew D Ruehl
- Chemical and Fuel Cycle Technologies Division, Argonne National Laboratory, Lemont, IL, USA
| | - Krista L Hawthorne
- Chemical and Fuel Cycle Technologies Division, Argonne National Laboratory, Lemont, IL, USA
| | | | - David A Andersson
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Mark A Williamson
- Chemical and Fuel Cycle Technologies Division, Argonne National Laboratory, Lemont, IL, USA
| | - Richard Weber
- Materials Development, Inc., Arlington Heights, IL, USA
- X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
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Wilke SK, Al-Rubkhi A, Koyama C, Ishikawa T, Oda H, Topper B, Tsekrekas EM, Möncke D, Alderman OLG, Menon V, Rafferty J, Clark E, Kastengren AL, Benmore CJ, Ilavsky J, Neuefeind J, Kohara S, SanSoucie M, Phillips B, Weber R. Microgravity effects on nonequilibrium melt processing of neodymium titanate: thermophysical properties, atomic structure, glass formation and crystallization. NPJ Microgravity 2024; 10:26. [PMID: 38448495 PMCID: PMC10918169 DOI: 10.1038/s41526-024-00371-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/19/2024] [Indexed: 03/08/2024] Open
Abstract
The relationships between materials processing and structure can vary between terrestrial and reduced gravity environments. As one case study, we compare the nonequilibrium melt processing of a rare-earth titanate, nominally 83TiO2-17Nd2O3, and the structure of its glassy and crystalline products. Density and thermal expansion for the liquid, supercooled liquid, and glass are measured over 300-1850 °C using the Electrostatic Levitation Furnace (ELF) in microgravity, and two replicate density measurements were reproducible to within 0.4%. Cooling rates in ELF are 40-110 °C s-1 lower than those in a terrestrial aerodynamic levitator due to the absence of forced convection. X-ray/neutron total scattering and Raman spectroscopy indicate that glasses processed on Earth and in microgravity exhibit similar atomic structures, with only subtle differences that are consistent with compositional variations of ~2 mol. % Nd2O3. The glass atomic network contains a mixture of corner- and edge-sharing Ti-O polyhedra, and the fraction of edge-sharing arrangements decreases with increasing Nd2O3 content. X-ray tomography and electron microscopy of crystalline products reveal substantial differences in microstructure, grain size, and crystalline phases, which arise from differences in the melt processes.
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Affiliation(s)
- Stephen K Wilke
- Materials Development, Inc., Evanston, IL, 60202, USA.
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA.
| | | | | | | | - Hirohisa Oda
- Japan Aerospace Exploration Agency, Tsukuba, Japan
| | - Brian Topper
- Center for High Technology Materials, University of New Mexico, Albuquerque, NM, 87106, USA
| | - Elizabeth M Tsekrekas
- Inamori School of Engineering at the New York State College of Ceramics, Alfred University, Alfred, NY, 14802, USA
| | - Doris Möncke
- Inamori School of Engineering at the New York State College of Ceramics, Alfred University, Alfred, NY, 14802, USA
| | - Oliver L G Alderman
- ISIS Neutron & Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| | | | | | - Emma Clark
- Materials Development, Inc., Evanston, IL, 60202, USA
| | - Alan L Kastengren
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Chris J Benmore
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jan Ilavsky
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jörg Neuefeind
- Neutron Science Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Shinji Kohara
- National Institute for Materials Science, Tsukuba, Japan
| | | | | | - Richard Weber
- Materials Development, Inc., Evanston, IL, 60202, USA
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
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Beigbeder T, Bourasseau E, Rushton M. Thermophysical properties of liquid (U, Zr)O2 by molecular dynamics. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1987429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Théo Beigbeder
- CEA, DES, IRESNE, DEC, SESC, LM2C, Saint-Paul-Lez-Durance, France
| | | | - Michael Rushton
- Nuclear Futures Institute, Bangor University, Bangor Gwynedd, UK
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Thermal Analysis of High-Entropy Rare Earth Oxides. MATERIALS 2020; 13:ma13143141. [PMID: 32674493 PMCID: PMC7412006 DOI: 10.3390/ma13143141] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/04/2020] [Accepted: 07/06/2020] [Indexed: 12/03/2022]
Abstract
Phase transformations in multicomponent rare earth sesquioxides were studied by splat quenching from the melt, high temperature differential thermal analysis and synchrotron X-ray diffraction on laser-heated samples. Three compositions were prepared by the solution combustion method: (La,Sm,Dy,Er,RE)2O3, where all oxides are in equimolar ratios and RE is Nd or Gd or Y. After annealing at 800 °C, all powders contained mainly a phase of C-type bixbyite structure. After laser melting, all samples were quenched in a single-phase monoclinic B-type structure. Thermal analysis indicated three reversible phase transitions in the range 1900–2400 °C, assigned as transformations into A, H, and X rare earth sesquioxides structure types. Unit cell volumes and volume changes on C-B, B-A, and H-X transformations were measured by X-ray diffraction and consistent with the trend in pure rare earth sesquioxides. The formation of single-phase solid solutions was predicted by Calphad calculations. The melting point was determined for the (La,Sm,Dy,Er,Nd)2O3 sample as 2456 ± 12 °C, which is higher than for any of constituent oxides. An increase in melting temperature is probably related to nonideal mixing in the solid and/or the melt and prompts future investigation of the liquidus surface in Sm2O3-Dy2O3, Sm2O3-Er2O3, and Dy2O3-Er2O3 systems.
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Agca C, Neuefeind JC, McMurray JW, Liu J, Benmore CJ, Weber RJK, Navrotsky A. In Situ High-Temperature Synchrotron Diffraction Studies of (Fe,Cr,Al) 3O 4 Spinels. Inorg Chem 2020; 59:5949-5957. [PMID: 32320222 DOI: 10.1021/acs.inorgchem.9b03726] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The modeling of a loss-of-coolant-accident scenario involving nuclear fuels with FeCrAl cladding materials in consideration to replace a Zircaloy requires knowledge of the thermodynamics of oxidized structures. At temperatures higher than 1500 °C, oxidation of FeCrAl alloys forms (Fe,Cr,Al)3O4 spinels. In situ high-energy X-ray diffraction in a conical nozzle levitator installed at beamline 6-ID-D of the APS was used to study the structural evolution of the oxides as a function of the temperature. Single-phase (spinel) and multiphase (spinel-corundum-FeAlO3) regions are mapped as a function of the temperature for three different compositions of FeCrAl oxidation products. The thermal expansion coefficients and cation distribution in the spinel structure have been refined. The temperature at which complete melting of the fuel cladding is expected has been determined by the liquidus temperatures of the oxidized products to be between 1657 and 1834 °C in a 20% O2/Ar atmosphere using the cooling trace method. The liquidus temperature increases with increasing Al and Cr content in the spinel phase.
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Affiliation(s)
- Can Agca
- Peter A. Rock Thermochemistry Laboratory, University of California-Davis (UC Davis), Davis, California 95616, United States.,Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Jörg C Neuefeind
- Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Jake W McMurray
- Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Jue Liu
- Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Chris J Benmore
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Richard J K Weber
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), 9700 South Cass Avenue, Argonne, Illinois 60439, United States.,Materials Development, Inc., Arlington Heights, Illinois 60004, United States
| | - Alexandra Navrotsky
- Peter A. Rock Thermochemistry Laboratory, University of California-Davis (UC Davis), Davis, California 95616, United States.,Center for Materials of the Universe, School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
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Density and viscosity of liquid ZrO 2 measured by aerodynamic levitation technique. Heliyon 2019; 5:e02049. [PMID: 31372532 PMCID: PMC6658727 DOI: 10.1016/j.heliyon.2019.e02049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 05/13/2019] [Accepted: 07/03/2019] [Indexed: 11/20/2022] Open
Abstract
Liquid ZrO2 is one of the most important materials involved in severe accident analysis of a light-water reactor. Despite its importance, the physical properties of liquid ZrO2 are scarcely reported. In particular, there are no experimental reports on the viscosity of liquid ZrO2. This is mainly due to the technical difficulties involved in the measurement of thermo-physical properties of liquid ZrO2, which has an extremely high melting point. To address this problem, an aerodynamic levitation technique was used in this study. The density of liquid ZrO2 was calculated from its mass and volume, estimated based on the recorded image of the sample. The viscosity was measured by a droplet oscillation technique. The density and viscosity of liquid ZrO2 at temperatures ranging from 2753 K to 3273 K, and 3170 K-3471 K, respectively, were successfully evaluated. The density of liquid ZrO2 was found to be 4.7 g/cm 3 at its melting point of 2988 K and decreased linearly with increasing temperature, and the viscosity of liquid ZrO2 was 13 mPa at its melting point.
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