Uranium isotope variation within vein-type uranium ore deposits

Anya C Keatley; James A Dunne; Tomas L Martin; Dan C Nita; Morten B. Andersen; Thomas Bligh Scott; David A Richards; Roy Awbery

doi:10.1016/j.apgeochem.2021.104977

Uranium isotope variation within vein-type uranium ore deposits

Anya C Keatley, James A Dunne^*, Tomas L Martin, Dan C Nita, Morten B. Andersen, Thomas Bligh Scott , David A Richards, Roy Awbery

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

Abstract

Isotopic composition of uranium has previously been used to infer the depositional redox environment of uranium ore concentrates and also provide a potential signature to inform nuclear forensic investigations. This study evaluates the diagnostic power of the U isotope signature by investigating (1) the heterogeneity of U isotope compositions in samples collected from the same mine and/or vein, and (2) the influence of U ore processing on 238U/235U and 234U/238U ratios. These characteristics are explored via high precision mass spectrometric measurement of vein type uranium ore samples collected predominantly from mines located in central Portugal and Southwest England. Samples collected from the same vein and mine exhibit δ238U values from −0.16 to +0.03 (±0.04) ‰ and −1.6 to −64.7 (±0.4) ‰ for δ234U (±2SD). These variations can be attributed to redox-driven isotope fractionation processes and/or U redistribution during localised leaching and re-precipitation. Analyses of residues and leachates from small-scale batch experiments designed to simulate industrial U ore leaching procedures reveal significant positive and negative changes in isotope composition in the leachate relative to the bulk material (up to 0.21 ± 0.06‰ for δ238U and 62.0 ± 0.6‰ for δ234U). These findings highlight the possibility of significantly different δ238U and δ234U of uranium ore concentrate from the same mine even if manufacturing processes remain unchanged.

Original language	English
Article number	104977
Number of pages	10
Journal	Applied Geochemistry
Volume	131
Early online date	12 May 2021
DOIs	https://doi.org/10.1016/j.apgeochem.2021.104977
Publication status	Published - 1 Aug 2021

Bibliographical note

Funding Information:
The authors wish to extend thanks to the Cabot Institute, University of Bristol , for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laboratório de Protecção e Segurança Radiológica at Unidade de Protecção e Segurança Radiológica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper.

Funding Information:
The authors wish to extend thanks to the Cabot Institute, University of Bristol, for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laborat?rio de Protec??o e Seguran?a Radiol?gica at Unidade de Protec??o e Seguran?a Radiol?gica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper.

Publisher Copyright:
© 2021

Keywords

Nuclear forensics
Uranium
Isotopic fractionation
Uranium ore concentrates

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3 Article (Academic Journal)
1 Letter (Academic Journal)

Machine learning techniques to repurpose Uranium Ore Concentrate (UOC) industrial records and their application to nuclear forensic investigation
Jones, A., Keatley, A. C., Goulermas, J. Y., Scott, T. B., Turner, P., Awbery, R. & Stapleton, M., 1 Apr 2018, In: Applied Geochemistry. 91, p. 221-227 7 p.
Research output: Contribution to journal › Article (Academic Journal) › peer-review
8 Citations (Scopus)
Source identification of uranium-containing materials at mine legacy sites in Portugal
Keatley, A. C., Martin, P. G., Hallam, K. R., Payton, O. D., Awbery, R., Carvalho, F., Oliveira, J. M., Silva, L., Malta, M. & Scott, T. B., 1 Mar 2018, In: Journal of Environmental Radioactivity. 183, p. 102-111 10 p.
Research output: Contribution to journal › Article (Academic Journal) › peer-review
9 Citations (Scopus)
An investigation into heterogeneity in a single vein-type uranium ore deposit: Implications for nuclear forensics
Keatley, A. C., Scott, T. B., Davis, S. & Jones, C. P., 1 Dec 2015, In: Journal of Environmental Radioactivity. 150, p. 75-85 11 p.
Research output: Contribution to journal › Article (Academic Journal) › peer-review
7 Citations (Scopus)

Cite this

@article{fa22bfa018e6491ea22fd817adf41807,

title = "Uranium isotope variation within vein-type uranium ore deposits",

abstract = "Isotopic composition of uranium has previously been used to infer the depositional redox environment of uranium ore concentrates and also provide a potential signature to inform nuclear forensic investigations. This study evaluates the diagnostic power of the U isotope signature by investigating (1) the heterogeneity of U isotope compositions in samples collected from the same mine and/or vein, and (2) the influence of U ore processing on 238U/235U and 234U/238U ratios. These characteristics are explored via high precision mass spectrometric measurement of vein type uranium ore samples collected predominantly from mines located in central Portugal and Southwest England. Samples collected from the same vein and mine exhibit δ238U values from −0.16 to +0.03 (±0.04) ‰ and −1.6 to −64.7 (±0.4) ‰ for δ234U (±2SD). These variations can be attributed to redox-driven isotope fractionation processes and/or U redistribution during localised leaching and re-precipitation. Analyses of residues and leachates from small-scale batch experiments designed to simulate industrial U ore leaching procedures reveal significant positive and negative changes in isotope composition in the leachate relative to the bulk material (up to 0.21 ± 0.06‰ for δ238U and 62.0 ± 0.6‰ for δ234U). These findings highlight the possibility of significantly different δ238U and δ234U of uranium ore concentrate from the same mine even if manufacturing processes remain unchanged.",

keywords = "Nuclear forensics, Uranium, Isotopic fractionation, Uranium ore concentrates",

author = "Keatley, {Anya C} and Dunne, {James A} and Martin, {Tomas L} and Nita, {Dan C} and Andersen, {Morten B.} and Scott, {Thomas Bligh} and Richards, {David A} and Roy Awbery",

note = "Funding Information: The authors wish to extend thanks to the Cabot Institute, University of Bristol , for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laborat{\'o}rio de Protec{\c c}{\~a}o e Seguran{\c c}a Radiol{\'o}gica at Unidade de Protec{\c c}{\~a}o e Seguran{\c c}a Radiol{\'o}gica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper. Funding Information: The authors wish to extend thanks to the Cabot Institute, University of Bristol, for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laborat?rio de Protec??o e Seguran?a Radiol?gica at Unidade de Protec??o e Seguran?a Radiol?gica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper. Publisher Copyright: {\textcopyright} 2021",

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doi = "10.1016/j.apgeochem.2021.104977",

language = "English",

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AU - Dunne, James A

AU - Martin, Tomas L

AU - Nita, Dan C

AU - Andersen, Morten B.

AU - Scott , Thomas Bligh

AU - Richards, David A

AU - Awbery, Roy

N1 - Funding Information: The authors wish to extend thanks to the Cabot Institute, University of Bristol , for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laboratório de Protecção e Segurança Radiológica at Unidade de Protecção e Segurança Radiológica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper. Funding Information: The authors wish to extend thanks to the Cabot Institute, University of Bristol, for supporting this work and AWE plc for funding [contract reference: 30218761]. Additional thanks to Tim Elliott and Christopher Coath, Bristol Isotope Group, University of Bristol. The authors also wish to acknowledge Laborat?rio de Protec??o e Seguran?a Radiol?gica at Unidade de Protec??o e Seguran?a Radiol?gica for their assistance during fieldwork and sample collection. We are grateful to the two anonymous reviewers for their suggested improvements to this paper. Publisher Copyright: © 2021

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N2 - Isotopic composition of uranium has previously been used to infer the depositional redox environment of uranium ore concentrates and also provide a potential signature to inform nuclear forensic investigations. This study evaluates the diagnostic power of the U isotope signature by investigating (1) the heterogeneity of U isotope compositions in samples collected from the same mine and/or vein, and (2) the influence of U ore processing on 238U/235U and 234U/238U ratios. These characteristics are explored via high precision mass spectrometric measurement of vein type uranium ore samples collected predominantly from mines located in central Portugal and Southwest England. Samples collected from the same vein and mine exhibit δ238U values from −0.16 to +0.03 (±0.04) ‰ and −1.6 to −64.7 (±0.4) ‰ for δ234U (±2SD). These variations can be attributed to redox-driven isotope fractionation processes and/or U redistribution during localised leaching and re-precipitation. Analyses of residues and leachates from small-scale batch experiments designed to simulate industrial U ore leaching procedures reveal significant positive and negative changes in isotope composition in the leachate relative to the bulk material (up to 0.21 ± 0.06‰ for δ238U and 62.0 ± 0.6‰ for δ234U). These findings highlight the possibility of significantly different δ238U and δ234U of uranium ore concentrate from the same mine even if manufacturing processes remain unchanged.

AB - Isotopic composition of uranium has previously been used to infer the depositional redox environment of uranium ore concentrates and also provide a potential signature to inform nuclear forensic investigations. This study evaluates the diagnostic power of the U isotope signature by investigating (1) the heterogeneity of U isotope compositions in samples collected from the same mine and/or vein, and (2) the influence of U ore processing on 238U/235U and 234U/238U ratios. These characteristics are explored via high precision mass spectrometric measurement of vein type uranium ore samples collected predominantly from mines located in central Portugal and Southwest England. Samples collected from the same vein and mine exhibit δ238U values from −0.16 to +0.03 (±0.04) ‰ and −1.6 to −64.7 (±0.4) ‰ for δ234U (±2SD). These variations can be attributed to redox-driven isotope fractionation processes and/or U redistribution during localised leaching and re-precipitation. Analyses of residues and leachates from small-scale batch experiments designed to simulate industrial U ore leaching procedures reveal significant positive and negative changes in isotope composition in the leachate relative to the bulk material (up to 0.21 ± 0.06‰ for δ238U and 62.0 ± 0.6‰ for δ234U). These findings highlight the possibility of significantly different δ238U and δ234U of uranium ore concentrate from the same mine even if manufacturing processes remain unchanged.

KW - Nuclear forensics

KW - Uranium

KW - Isotopic fractionation

KW - Uranium ore concentrates

U2 - 10.1016/j.apgeochem.2021.104977

DO - 10.1016/j.apgeochem.2021.104977

M3 - Article (Academic Journal)

VL - 131

JO - Applied Geochemistry

JF - Applied Geochemistry

SN - 0883-2927

M1 - 104977

ER -

Uranium isotope variation within vein-type uranium ore deposits

Abstract

Bibliographical note

Keywords

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Research output

Machine learning techniques to repurpose Uranium Ore Concentrate (UOC) industrial records and their application to nuclear forensic investigation

Source identification of uranium-containing materials at mine legacy sites in Portugal

An investigation into heterogeneity in a single vein-type uranium ore deposit: Implications for nuclear forensics

Cite this