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Chen H, Nabiei F, Badro J, Alexander DTL, Hébert C. Non-negative matrix factorization-aided phase unmixing and trace element quantification of STEM-EDXS data. Ultramicroscopy 2024; 263:113981. [PMID: 38805837 DOI: 10.1016/j.ultramic.2024.113981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/27/2023] [Accepted: 04/25/2024] [Indexed: 05/30/2024]
Abstract
Energy-dispersive X-ray spectroscopy (EDXS) mapping with a scanning transmission electron microscope (STEM) is commonly used for chemical characterization of materials. However, STEM-EDXS quantification becomes challenging when the phases constituting the sample under investigation share common elements and overlap spatially. In this paper, we present a methodology to identify, segment, and unmix phases with a substantial spectral and spatial overlap in a semi-automated fashion through combining non-negative matrix factorization with a priori knowledge of the sample. We illustrate the methodology using a sample taken from an electron beam-sensitive mineral assemblage representing Earth's deep mantle. With it, we retrieve the true EDX spectra of the constituent phases and their corresponding phase abundance maps. It further enables us to achieve a reliable quantification for trace elements having concentration levels of ∼100 ppm. Our approach can be adapted to aid the analysis of many materials systems that produce STEM-EDXS datasets having phase overlap and/or limited signal-to-noise ratio (SNR) in spatially-integrated spectra.
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Affiliation(s)
- Hui Chen
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | | | - James Badro
- Earth and Planetary Science Laboratory (EPSL), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland; Université Sorbonne Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris FR-75005, France
| | - Duncan T L Alexander
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Cécile Hébert
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
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Son J, Riechers SL, Yu XY. Microscale Electrochemical Corrosion of Uranium Oxide Particles. MICROMACHINES 2023; 14:1727. [PMID: 37763890 PMCID: PMC10537459 DOI: 10.3390/mi14091727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023]
Abstract
Understanding the corrosion of spent nuclear fuel is important for the development of long-term storage solutions. However, the risk of radiation contamination presents challenges for experimental analysis. Adapted from the system for analysis at the liquid-vacuum interface (SALVI), we developed a miniaturized uranium oxide (UO2)-attached working electrode (WE) to reduce contamination risk. To protect UO2 particles in a miniatured electrochemical cell, a thin layer of Nafion was formed on the surface. Atomic force microscopy (AFM) shows a dense layer of UO2 particles and indicates their participation in electrochemical reactions. Particles remain intact on the electrode surface with slight redistribution. X-ray photoelectron spectroscopy (XPS) reveals a difference in the distribution of U(IV), U(V), and U(VI) between pristine and corroded UO2 electrodes. The presence of U(V)/U(VI) on the corroded electrode surface demonstrates that electrochemically driven UO2 oxidation can be studied using these cells. Our observations of U(V) in the micro-electrode due to the selective semi-permeability of Nafion suggest that interfacial water plays a key role, potentially simulating a water-lean scenario in fuel storage conditions. This novel approach offers analytical reproducibility, design flexibility, a small footprint, and a low irradiation dose, while separating the α-effect. This approach provides a valuable microscale electrochemical platform for spent fuel corrosion studies with minimal radiological materials and the potential for diverse configurations.
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Affiliation(s)
- Jiyoung Son
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Shawn L. Riechers
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Xiao-Ying Yu
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37830, USA
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Yao J, Lahiri N, Tripathi S, Riechers SL, Ilton ES, Chatterjee S, Buck EC. A microfluidic electrochemical cell for studying the corrosion of uranium dioxide (UO 2). RSC Adv 2022; 12:19350-19358. [PMID: 35865596 PMCID: PMC9251908 DOI: 10.1039/d2ra02501a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/26/2022] [Indexed: 11/21/2022] Open
Abstract
We have developed a specialized microfluidic electrochemical cell that enables in situ investigation of the electrochemical corrosion of microgram quantities of redox active solids. The advantage of downscaling is the reduction of hazards, waste, expense, and greatly expanding data collection for hazardous materials, including radioactive samples. Cyclic voltammetry was used to monitor the oxidation–reduction cycle of minute quantities of micron-size uraninite (UO2) particles, from the formation of hexavalent uranium (U(vi)), U3O7 and reduction to UO2+x. Reaction progress was also studied in situ with scanning electron microscopy. The electrochemical measurements matched those obtained at the bulk-scale and were consistent with ex situ characterization of the run products by X-ray photoelectron spectroscopy, scanning transmission electron microscopy, and atomic force microscopy; thus, demonstrating the utility of the microfluidic approach for studying radioactive materials. Highlight of the multimodal characterization of corrosion behaviour of microgram quantities of UO2, enabled by a novel particle-attached microfluidic electrochemical cell.![]()
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Affiliation(s)
- Jennifer Yao
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Nabajit Lahiri
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Shalini Tripathi
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Shawn L Riechers
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Eugene S Ilton
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Sayandev Chatterjee
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
| | - Edgar C Buck
- Pacific Northwest National Laboratory 902 Battelle Blvd. P.O. Box 999 Richland WA 99354 USA
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Hurley DH, El-Azab A, Bryan MS, Cooper MWD, Dennett CA, Gofryk K, He L, Khafizov M, Lander GH, Manley ME, Mann JM, Marianetti CA, Rickert K, Selim FA, Tonks MR, Wharry JP. Thermal Energy Transport in Oxide Nuclear Fuel. Chem Rev 2021; 122:3711-3762. [PMID: 34919381 DOI: 10.1021/acs.chemrev.1c00262] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To efficiently capture the energy of the nuclear bond, advanced nuclear reactor concepts seek solid fuels that must withstand unprecedented temperature and radiation extremes. In these advanced fuels, thermal energy transport under irradiation is directly related to reactor performance as well as reactor safety. The science of thermal transport in nuclear fuel is a grand challenge as a result of both computational and experimental complexities. Here we provide a comprehensive review of thermal transport research on two actinide oxides: one currently in use in commercial nuclear reactors, uranium dioxide (UO2), and one advanced fuel candidate material, thorium dioxide (ThO2). In both materials, heat is carried by lattice waves or phonons. Crystalline defects caused by fission events effectively scatter phonons and lead to a degradation in fuel performance over time. Bolstered by new computational and experimental tools, researchers are now developing the foundational work necessary to accurately model and ultimately control thermal transport in advanced nuclear fuels. We begin by reviewing research aimed at understanding thermal transport in perfect single crystals. The absence of defects enables studies that focus on the fundamental aspects of phonon transport. Next, we review research that targets defect generation and evolution. Here the focus is on ion irradiation studies used as surrogates for damage caused by fission products. We end this review with a discussion of modeling and experimental efforts directed at predicting and validating mesoscale thermal transport in the presence of irradiation defects. While efforts in these research areas have been robust, challenging work remains in developing holistic tools to capture and predict thermal energy transport across widely varying environmental conditions.
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Affiliation(s)
- David H Hurley
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Anter El-Azab
- School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Matthew S Bryan
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Michael W D Cooper
- Materials Science and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Cody A Dennett
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Krzysztof Gofryk
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Lingfeng He
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Marat Khafizov
- Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 West 19th Ave, Columbus, Ohio 43210, United States
| | - Gerard H Lander
- European Commission, Joint Research Center, Postfach 2340, D-76125 Karlsruhe, Germany
| | - Michael E Manley
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - J Matthew Mann
- U.S. Air Force Research Laboratory, Sensors Directorate, 2241 Avionics Circle, Wright Patterson AFB, Ohio 45433, United States
| | - Chris A Marianetti
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Karl Rickert
- KBR, 2601 Mission Point Boulevard, Suite 300, Dayton, Ohio 45431, United States
| | - Farida A Selim
- Department of Physics and Astronomy, Bowling Green State University, 705 Ridge Street, Bowling Green, Ohio 43403, United States
| | - Michael R Tonks
- Department of Materials Science and Engineering, University of Florida, 158 Rhines Hall, Gainesville, Florida 32611, United States
| | - Janelle P Wharry
- School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, Indiana 47907, United States
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Majumdar A, Manukyan KV, Dede S, Roach JM, Robertson D, Burns PC, Aprahamian A. Irradiation-Driven Restructuring of UO 2 Thin Films: Amorphization and Crystallization. ACS APPLIED MATERIALS & INTERFACES 2021; 13:35153-35164. [PMID: 34270887 DOI: 10.1021/acsami.1c08682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Combustion synthesis in uranyl nitrate-acetylacetone-2-methoxyethanol solutions was used to deposit thin UO2 films on aluminum substrates to investigate the irradiation-induced restructuring processes. Thermal analysis revealed that the combustion reactions in these solutions are initiated at ∼160 °C. The heat released during the process and the subsequent brief annealing at 400 °C allow the deposition of polycrystalline films with 5-10 nm UO2 grains. The use of multiple deposition cycles enables tuning of the film thicknesses in the 35-260 nm range. Irradiation with Ar2+ ions (1.7 MeV energy and a fluence of up to 1 × 1017 ions/cm2) is utilized to generate a uniform distribution of atomic displacements within the films. X-ray fluorescence (XRF) and alpha-particle emission spectroscopy showed that the films were stable under irradiation and did not undergo sputtering degradation. X-ray photoelectron spectroscopy (XPS) showed that the stoichiometry and uranium ionic concentrations remain stable during irradiation. The high-resolution electron microscopy imaging and electron diffraction analysis demonstrated that at the early stages of irradiation (below 1 × 1016 ion/cm2) UO2 films show complete amorphization and beam-induced densification (sintering), resulting in a pore-free disordered film. Prolonged irradiation (5 × 1016 ion/cm2) is shown to trigger a crystallization process at the surface of the films that moves toward the UO2/Al interface, converting the entire amorphous material into a highly crystalline film. This work reports on an entirely different radiation-induced restructuring of the nanoscale UO2 compared to the coarse-grained counterpart. The preparation of thin UO2 films deposited on Al substrates fills an area of national need within the stockpile stewardship program of the National Nuclear Security Administration and fundamental research with actinides. The method reported in this work produces pure, robust, and uniform thin-film actinide targets for nuclear science measurements.
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Affiliation(s)
- Ashabari Majumdar
- Nuclear Science Laboratory, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Khachatur V Manukyan
- Nuclear Science Laboratory, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Stefania Dede
- Nuclear Science Laboratory, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, United States
| | - Jordan M Roach
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Daniel Robertson
- Nuclear Science Laboratory, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Peter C Burns
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Ani Aprahamian
- Nuclear Science Laboratory, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
- A. Alikhanyan National Science Laboratory of Armenia, 2 Alikhanyan Brothers, 0036 Yerevan, Armenia
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El Jamal G, Gouder T, Eloirdi R, Jonsson M. Time-dependent surface modification of uranium oxides exposed to water plasma. Dalton Trans 2021; 50:4796-4804. [PMID: 33877177 DOI: 10.1039/d1dt00486g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thin UO2 films exposed to water plasma under UHV conditions have been shown to be interesting models for radiation induced oxidative dissolution of spent nuclear fuel. This is partly attributed to the fact that several of the reactive oxidizing and reducing species in a water plasma are also identified as products of radiolysis of water. Exposure of UO2 films to water plasma has previously been shown to lead to oxidation from U(iv) to U(v) and (vi). In this work we have studied the dynamics of water plasma induced redox changes in UO2 films by monitoring UO2 films using X-Ray photoelectron Photoemission (XPS) and Ultra-Violet Photoemission (UPS) spectroscopy as a function of exposure time. The surface composition in terms of oxidation states obtained from U4f7/2 peak deconvolution could be retraced along the exposure time, and compared to the valence band. The spectral analysis showed that U(iv) is initially oxidized to U(v) which is subsequently oxidized to U(vi). For extended exposure times it was shown that U(vi) is slowly reduced back to U(v). UPS data show that, unlike the U(v) formed on the surface upon oxidation of U(iv), the U(v) formed upon reduction of U(vi) is localized in the bulk of the film. It also displays a different reactivity than the initially formed U(v). The experiments can be reproduced using a simple kinetic model describing the redox processes involved.
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Affiliation(s)
- Ghada El Jamal
- School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Department of Chemistry, Applied Physical Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
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El Jamal G, Gouder T, Eloirdi R, Jonsson M. X-Ray and ultraviolet photoelectron spectroscopy studies of Uranium(iv),(v) and(vi) exposed to H2O-plasma under UHV conditions. Dalton Trans 2021; 50:729-738. [DOI: 10.1039/d0dt03562a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report surface characteristics of UO2, U2O5 and UO3 thin films after exposure to gas plasmas: a new approach of the oxidative dissolution problem.
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Affiliation(s)
- Ghada El Jamal
- KTH
- School of Engineering Sciences in Chemistry
- Biotechnology and Health (CBH)
- Department of Chemistry
- Applied Physical Chemistry
| | - Thomas Gouder
- European Commission
- Joint Research Centre
- Directorate for Nuclear Safety and Security
- DE-76215 Karlsruhe
- Germany
| | - Rachel Eloirdi
- European Commission
- Joint Research Centre
- Directorate for Nuclear Safety and Security
- DE-76215 Karlsruhe
- Germany
| | - Mats Jonsson
- KTH
- School of Engineering Sciences in Chemistry
- Biotechnology and Health (CBH)
- Department of Chemistry
- Applied Physical Chemistry
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