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Villa-Aleman E, Kwapis EH, Foley BJ, Shehee TC, Dick DD, Darvin JR, Ajo HM, Hartig KC. Laser-Induced Plasmas of Plutonium Dioxide in a Double-Walled Cell. APPLIED SPECTROSCOPY 2024; 78:412-422. [PMID: 38317274 DOI: 10.1177/00037028241226977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Plutonium research has been stifled by the significant number of administrative controls and safety procedures, space and instrumentation limitations in radiological gloveboxes, and the potential for personnel and equipment contamination. To address the limited number of spectroscopic studies in Pu-bearing compounds in the current scientific literature, this work presents the use of double-walled cells (DWCs) in "clean" buildings/laboratories as an alternative to research in radiological gloveboxes. This study reports the first laser-induced breakdown spectroscopy (LIBS) experiments of a PuO2 pellet contained within a DWC, where the formation of elemental (atomic and ionic) species as well as the evolution from elemental to molecular products (PuxOy) was measured. Raman spectroscopy was also used to characterize the surface of the ablated pellet and the particulates deposited on the window of the inner cell. The full width half-maximum of the T2g band enabled us to obtain an estimate of the temperature at the pellet surface after the ablation pulse and the particulates based on the crystal lattice disorder. Particulates deposited on the window of the DWC during laser ablation were characterized using scanning electron microscopy, where molten irregular particulates and spheroids were observed. This exciting research conducted in a DWC describes our initial attempts to incorporate LIBS in the arsenal of spectroscopic tools for nuclear forensics applications.
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Affiliation(s)
| | - Emily H Kwapis
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Flordia, USA
| | - Bryan J Foley
- Savannah River National Laboratory, Aiken, South Carolina, USA
| | - Thomas C Shehee
- Savannah River National Laboratory, Aiken, South Carolina, USA
| | - Don D Dick
- Savannah River National Laboratory, Aiken, South Carolina, USA
| | - Jason R Darvin
- Savannah River National Laboratory, Aiken, South Carolina, USA
| | - Henry M Ajo
- Savannah River National Laboratory, Aiken, South Carolina, USA
| | - Kyle C Hartig
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Flordia, USA
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2
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Sockwell AK, Sweet TFM, Barth B, Burns PC, Hixon AE. Pu(VI) Oxalate Crystal Structure and Evidence of Photoreduction to Pu(IV) Oxalate. Inorg Chem 2024; 63:56-60. [PMID: 38117695 DOI: 10.1021/acs.inorgchem.3c03786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
We report the first crystal structure of a Pu(VI)-oxalate compound. This compound, [PuO2(C2O4)(H2O)]·2(H2O) (1), crystallizes in space group P21/c with a = 5.5993(3) Å, b = 16.8797(12) Å, c = 9.3886(6) Å, and β = 98.713(6)°. It is isostructural with the previously reported U(VI) compound, [UO2(C2O4)(H2O)]·2(H2O). Each plutonyl ion (PuO22+) is coordinated in the equatorial plane by two side-on bidentate oxalates, creating an infinite chain along [001]. A coordinated water molecule and twisting of the oxalates lead to a distorted pentagonal bipyramidal geometry of the Pu. A photochemical degradation was observed for 1, which resulted in the formation of a secondary crystalline phase. The absorption spectrum of this secondary phase confirmed the presence of Pu(IV), but it did not match the spectrum of Pu(C2O4)2·6H2O, which is considered to be the primary product of Pu-oxalate precipitation. While compound 1 has previously been proposed to exist in solution, this is the first time it has been isolated via crystallization. Although redox interactions between Pu and oxalate have been documented in the literature, the present study is the first observation of a photochemical reduction of Pu(VI)-oxalate. As a result, this study has expanded on the limited understanding of the Pu(VI)-oxalate system, which is important for nuclear fuel cycle applications.
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Affiliation(s)
- A Kirstin Sockwell
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Teagan F M Sweet
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Brodie Barth
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Peter C Burns
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Amy E Hixon
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Sockwell AK, DiBlasi NA, Hixon AE. A spectrophotometric study of the impact of pH and metal-to-ligand ratio on the speciation of the Pu(VI)-oxalate system. Phys Chem Chem Phys 2023. [PMID: 38018253 DOI: 10.1039/d3cp04010k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The oxalate ligand is prevalent throughout the nuclear fuel cycle. While the Pu(III)- and Pu(IV)-oxalate systems are well studied due to their use in plutonium metal and PuO2 production, the effect of oxalate on Pu(VI) remains understudied. Absorption spectroscopy was employed to probe the solution behavior of the Pu(VI)-oxalate system as a function of pH (1, 3, 7) and metal-to-ligand ratio (M/L; 10 : 1-1 : 10). Peak changes in the UV-vis-NIR spectra were associated with the formation of multiple Pu(VI)-oxalate species with increasing oxalate concentration. Some insight into identification of species present in solution was gained from the limited Pu(VI)-oxalate literature and comparisons with the assumed isostructural U(VI)-oxalate system. A peak in the UV-vis-NIR spectrum at 839 nm, which corresponds to the formation of a 1 : 1 PuO2(C2O4)(aq) complex, was observed and used to determine the formation constant (log β° = 4.64 ± 0.06). A higher coordinated Pu(VI)-oxalate peak at 846 nm was tentatively assigned as the 1 : 2 complex PuO2(C2O4)22- and a preliminary formation constant was determined (log β° = 9.30 ± 0.08). The predominance of both complexes was shown in speciation diagrams calculated from the formation constants, illustrating the importance of considering the Pu(VI)-oxalate system in the nuclear fuel cycle.
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Affiliation(s)
- A Kirstin Sockwell
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Nicole A DiBlasi
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Amy E Hixon
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
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Villa-Aleman E, Christian JH, Darvin JR, Foley BJ, Dick DD, Fallin B, Fessler KAS. Diffuse Reflectance Spectroscopy and Principal Component Analysis to Retrospectively Determine Production History of Plutonium Dioxide. APPLIED SPECTROSCOPY 2023; 77:449-456. [PMID: 36464665 DOI: 10.1177/00037028221145724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Diffuse reflectance spectroscopy measurements in the shortwave infrared (930-1600 nm) spectral region were acquired for Pu2(C2O4)3•9H2O and its thermal decomposition product, PuO2. We analyzed a total of eight PuO2 samples that were produced at different calcination temperatures (300, 350, 450, 525, 600, 675, 750, and 900 °C). Our goal was to identify spectroscopic fingerprints that could be used to gain retrospective information regarding the production parameters of these important nuclear compounds. The diffuse reflectance spectrum of Pu2(C2O4)3•9H2O features several broad bands that currently preclude detailed analysis. However, all PuO2 samples produced relatively sharp spectral features that got sharper and more intense for samples that were produced at higher calcination temperatures. The electronic band observed at 1433 nm in the diffuse reflectance spectra of PuO2 was found to be a sensitive indicator of crystallinity; a result that is corroborated by ancillary Raman spectroscopy measurements. Principal component analysis of diffuse reflectance spectra was able to clearly rank and categorize PuO2 samples based on the calcination temperature that was employed during their production. Thus, we show herein that important retrospective information pertaining to the process history of PuO2 can be gained through the relatively simplistic combination of diffuse reflectance spectroscopy and principal component analysis. This discovery presents a new method for determining the provenance and process history of PuO2 and should have an impact in the fields of nuclear forensics and nuclear nonproliferation.
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Affiliation(s)
| | | | | | | | - Don D Dick
- Savannah River National Laboratory, Aiken, SC, USA
| | - Brent Fallin
- Savannah River National Laboratory, Aiken, SC, USA
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Baumann V, Popa K, Walter O, Rivenet M, Senentz G, Morel B, Konings RJ. Synthesis of Nanocrystalline PuO 2 by Hydrothermal and Thermal Decomposition of Pu(IV) Oxalate: A Comparative Study. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:340. [PMID: 36678093 PMCID: PMC9865700 DOI: 10.3390/nano13020340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
In recent years, the hydrothermal conversion of actinide (IV) oxalates into nanometric actinide dioxides (AnO2) has begun to be investigated as an alternative to the widely implemented thermal decomposition method. We present here a comparison between the hydrothermal and the conventional thermal decomposition of Pu(IV) oxalate in terms of particle size, morphology and residual carbon content. A parametric study was carried out in order to define the temperature and time applied in the hydrothermal conversion of tetravalent Pu-oxalate into PuO2 and to optimize the reaction conditions.
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Affiliation(s)
- Viktoria Baumann
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181—UCCS—Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
- European Commission, Joint Research Centre, 76344 Karlsruhe, Germany
| | - Karin Popa
- European Commission, Joint Research Centre, 76344 Karlsruhe, Germany
| | - Olaf Walter
- European Commission, Joint Research Centre, 76344 Karlsruhe, Germany
| | - Murielle Rivenet
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181—UCCS—Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | | | | | - Rudy J.M. Konings
- European Commission, Joint Research Centre, 76344 Karlsruhe, Germany
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Kumar SS, Srivastava A, Rao A. Biodegradable Methane Sulfonic Acid-Based Nonaqueous Dissolution, Estimation, and Recovery: Toward Development of a Simplified Scheme for Plutonium-Bearing Fuel Matrices. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c03473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Shiny S. Kumar
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai400 085, India
- Homi Bhabha National Institute, Mumbai400094, India
| | - Ashutosh Srivastava
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai400 085, India
- Homi Bhabha National Institute, Mumbai400094, India
| | - Ankita Rao
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai400 085, India
- Homi Bhabha National Institute, Mumbai400094, India
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Virot M, Dumas T, Cot-Auriol M, Moisy P, Nikitenko SI. Synthesis and multi-scale properties of PuO 2 nanoparticles: recent advances and open questions. NANOSCALE ADVANCES 2022; 4:4938-4971. [PMID: 36504736 PMCID: PMC9680947 DOI: 10.1039/d2na00306f] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/15/2022] [Indexed: 05/28/2023]
Abstract
Due to the increased attention given to actinide nanomaterials, the question of their structure-property relationship is on the spotlight of recent publications. Plutonium oxide (PuO2) particularly plays a central role in nuclear energetics and a comprehensive knowledge about its properties when nanosizing is of paramount interest to understand its behaviour in environmental migration schemes but also for the development of advanced nuclear energy systems underway. The element plutonium further stimulates the curiosity of scientists due to the unique physical and chemical properties it exhibits around the periodic table. PuO2 crystallizes in the fluorite structure of the face-centered cubic system for which the properties can be significantly affected when shrinking. Identifying the formation mechanism of PuO2 nanoparticles, their related atomic, electronic and crystalline structures, and their reactivity in addition to their nanoscale properties, appears to be a fascinating and challenging ongoing topic, whose recent advances are discussed in this review.
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Affiliation(s)
- Matthieu Virot
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM Marcoule France
| | - Thomas Dumas
- CEA, DEN, DMRC, Univ Montpellier Marcoule France
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