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Kaplan U, Amayri S, Drebert J, Grolimund D, Reich T. Plutonium mobility and reactivity in a heterogeneous clay rock barrier accented by synchrotron-based microscopic chemical imaging. Sci Rep 2024; 14:3087. [PMID: 38321076 PMCID: PMC10847135 DOI: 10.1038/s41598-024-53189-8] [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: 08/04/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
The long-term safe disposal of radioactive waste corresponds to a challenging responsibility of present societies. Within deep geological waste disposal concepts, host rocks correspond to the ultimate safety barrier towards the environment. To assess the performance of such barriers over extended time scales, mechanistic information on the interaction between the radiotoxic, long-lived radionuclides like plutonium and the host rock is essential. Chemical imaging based on synchrotron microspectroscopic techniques was used to visualize undisturbed reactive transport patterns of Pu within pristine Opalinus Clay rock material. Pu+V is shown to be progressively reduced along its diffusion path to Pu+IV and Pu+III due to interaction with redox-active clay rock constituents. Experimental results and modeling emphasize the dominant role of electron-transfer reactions determining the mobility of Pu in reactive barrier systems. The effective migration velocity of Pu is controlled by the kinetic rates of the reduction to Pu+IV and Pu+III and the redox capacity of the involved electron donor pools. To advance our predictive capabilities further, an improved understanding of the nature and capacity of redox-active components of the reactive barrier material is fundamental. The findings represent an essential contribution to the evaluation of the long-term safety of potential nuclear waste repositories and have implications regarding the development of effective geological disposal strategies.
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Affiliation(s)
- U Kaplan
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - S Amayri
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - J Drebert
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - D Grolimund
- Swiss Light Source, Paul-Scherrer-Institut, 5232, Villigen PSI, Switzerland.
| | - T Reich
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.
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Deblonde GJP, Morrison K, Mattocks JA, Cotruvo JA, Zavarin M, Kersting AB. Impact of a Biological Chelator, Lanmodulin, on Minor Actinide Aqueous Speciation and Transport in the Environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20830-20843. [PMID: 37897703 DOI: 10.1021/acs.est.3c06033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/30/2023]
Abstract
Minor actinides are major contributors to the long-term radiotoxicity of nuclear fuels and other radioactive wastes. In this context, understanding their interactions with natural chelators and minerals is key to evaluating their transport behavior in the environment. The lanmodulin family of metalloproteins is produced by ubiquitous bacteria and Methylorubrum extorquens lanmodulin (LanM) was recently identified as one of nature's most selective chelators for trivalent f-elements. Herein, we investigated the behavior of neptunium, americium, and curium in the presence of LanM, carbonate ions, and common minerals (calcite, montmorillonite, quartz, and kaolinite). We show that LanM's aqueous complexes with Am(III) and Cm(III) remain stable in carbonate-bicarbonate solutions. Furthermore, the sorption of Am(III) to these minerals is strongly impacted by LanM, while Np(V) sorption is not. With calcite, even a submicromolar concentration of LanM leads to a significant reduction in the Am(III) distribution coefficient (Kd, from >104 to ∼102 mL/g at pH 8.5), rendering it even more mobile than Np(V). Thus, LanM-type chelators can potentially increase the mobility of trivalent actinides and lanthanide fission products under environmentally relevant conditions. Monitoring biological chelators, including metalloproteins, and their biogenerators should therefore be considered during the evaluation of radioactive waste repository sites and the risk assessment of contaminated sites.
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Affiliation(s)
- Gauthier J-P Deblonde
- Physical and Life Sciences Directorate, Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Keith Morrison
- Physical and Life Sciences Directorate, Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Joseph A Mattocks
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joseph A Cotruvo
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mavrik Zavarin
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Annie B Kersting
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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Schönenbach D, Berg F, Breckheimer M, Hagenlocher D, Schönberg P, Haas R, Amayri S, Reich T. Development, characterization, and first application of a resonant laser secondary neutral mass spectrometry setup for the research of plutonium in the context of long-term nuclear waste storage. Anal Bioanal Chem 2021; 413:3987-3997. [PMID: 33973021 PMCID: PMC8189947 DOI: 10.1007/s00216-021-03350-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/21/2021] [Accepted: 04/14/2021] [Indexed: 11/26/2022]
Abstract
Plutonium is a major contributor to the radiotoxicity in a long-term nuclear waste repository; therefore, many studies have focused on interactions of plutonium with the technical, geotechnical, and geological barriers of a possible nuclear waste storage site. In order to gain new insights into the sorption on surfaces and diffusion of actinides through these complex heterogeneous materials, a highly sensitive method with spatial resolution is required. Resonant laser secondary neutral mass spectrometry (Laser-SNMS) uses the spatial resolution available in time-of-flight secondary ion mass spectrometry (TOF-SIMS) in combination with the high selectivity, sensitivity, and low background noise of resonance ionization mass spectrometry (RIMS) and is, therefore, a promising method for the study and analysis of the geochemical behavior of plutonium in long-term nuclear waste storage. The authors present an approach with a combined setup consisting of a commercial TOF-SIMS instrument and a Ti:sapphire (Ti:Sa) laser system, as well as its optimization, characterization, and improvements compared to the original proof of concept by Erdmann et al. (2009). As a first application, the spatial distributions of plutonium and other elements on the surface of a pyrite particle and a cement thin section were measured by Laser-SNMS and TOF-SIMS, respectively. These results exemplify the potential of these techniques for the surface analysis of heterogeneous materials in the context of nuclear safety research.
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Affiliation(s)
- Daniela Schönenbach
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Felix Berg
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Markus Breckheimer
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Daniel Hagenlocher
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Pascal Schönberg
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Raphael Haas
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
- Helmholtz-Institut Mainz, 55099, Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
| | - Samer Amayri
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
| | - Tobias Reich
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.
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4
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Plutonium migration in a rough single fractured granite. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06981-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zavarin M, Zhao P, Joseph C, Begg JD, Boggs MA, Dai Z, Kersting AB. Hydrothermal Alteration of Nuclear Melt Glass, Colloid Formation, and Plutonium Mobilization at the Nevada National Security Site, U.S.A. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7363-7370. [PMID: 31192587 DOI: 10.1021/acs.est.8b07199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Approximately 2.8 t of plutonium (Pu) has been deposited in the Nevada National Security Site (NNSS) subsurface as a result of underground nuclear testing. Most of this Pu is sequestered in nuclear melt glass. However, Pu migration has been observed and attributed to colloid facilitated transport. To identify the mechanisms controlling Pu mobilization, long-term (∼3 year) laboratory nuclear melt glass alteration experiments were performed at 25 to 200 °C to mimic hydrothermal conditions in the vicinity of underground nuclear tests. The clay and zeolite colloids produced in these experiments are similar to those identified in NNSS groundwater. At 200 °C, maximum Pu and colloid concentrations of 30 Bq/L and 150 mg/L, respectively, were observed. However, much lower Pu and colloid concentrations were observed at 25 and 80 °C. These data suggest that Pu concentrations above the drinking water Maximum Contaminant Levels (0.56 Bq/L) may exist during early hydrothermal conditions in the vicinity of underground nuclear tests. However, formation of colloid-associated Pu will tend to decrease with time as nuclear test cavity temperatures decrease. Furthermore, median colloid concentrations in NNSS groundwater (1.8 mg/L) suggest that the high colloid and Pu concentrations observed in our 140 and 200 °C experiments are unlikely to persist in downgradient NNSS groundwater. While our experiments did not span all groundwater and nuclear melt glass conditions that may be present at the NNSS, our results are consistent with the documented low Pu concentrations in NNSS groundwater.
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Affiliation(s)
- Mavrik Zavarin
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Pihong Zhao
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Claudia Joseph
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - James D Begg
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Mark A Boggs
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Zurong Dai
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Annie B Kersting
- Glenn T. Seaborg Institute, Physical & Life Sciences , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
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