A review of technetium and zirconium extraction into tributyl phosphate in the PUREX process

George, K. C.; Masters, Andrew J.; Livens, Francis R.; Sarsfield, Mark J.; Taylor, Robin; Sharrad, Clint A.

doi:10.1016/j.hydromet.2022.105892

Cited by 33 publications

(18 citation statements)

References 73 publications

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“…Co-extraction of Tc with actinides and Zr(IV) (both as a radioactive fission product and non-radioactive fuel cladding) is a considerable challenge of the PUREX process, presumably by forming coordination complexes between hard metal cations and pertechnetate. 21 For example, it was prior-observed that TcO 4 − /ReO 4 − can coligate Th(IV), U(IV), and U(VI) along with organophosphorus ligands that are representative of the extractants used in the PUREX process. 22−24 These include tributyl phosphate (TBP), triethyl phosphate (TEP), tri-iso-butyl phosphate (T i BP), and tri-n-butyl phosphine oxide (TBPO).…”

Section: Introductionmentioning

confidence: 99%

“…The plutonium uranium redox extraction (PUREX) process involves dissolution of spent nuclear fuel (U and/or Pu oxides) in nitric acid, followed by extraction of the fuel elements in their highest oxidation state (i.e., U VI O 2 2+ , uranyl) into an organic phase, leaving behind the fission products and other non-radioactive components of fuel. Co-extraction of Tc with actinides and Zr(IV) (both as a radioactive fission product and non-radioactive fuel cladding) is a considerable challenge of the PUREX process, presumably by forming coordination complexes between hard metal cations and pertechnetate . For example, it was prior-observed that TcO 4 – /ReO 4 – can co-ligate Th(IV), U(IV), and U(VI) along with organophosphorus ligands that are representative of the extractants used in the PUREX process. − These include tributyl phosphate (TBP), triethyl phosphate (TEP), tri- iso -butyl phosphate (T i BP), and tri- n -butyl phosphine oxide (TBPO).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions

et al. 2023

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Technetium-99, a β-emitter produced from 235U fission, poses a challenge for the nuclear industry due to co-extraction of pertechnetate (TcO4 –) with the actinides (An) during nuclear fuel reprocessing. Previous studies suggested that direct coordination of pertechnetate with An plays an important role in the coextraction process. However, few studies have provided direct evidence for An–TcO4 – bonding in the solid state, and even fewer in solution. The present study describes synthesis and structural elucidation of a family of thorium(IV)-pertechnetate/perrhenate (ReO4 –, nonradioactive surrogate) compounds, which is obtained by dissolution of thorium oxyhydroxide in perrhenic/pertechnic acid followed by crystallization, with or without heating. For reaction ratios of 3:1, 4:1, and 6:1 MO4 –/Th(IV) (M = Tc, Re), the crystallized compounds reflect the same ratio, suggesting facile and flexible coordination. Nine structures reveal 1-dimensional and 2-dimensional frameworks with varying topologies. While a multitude of compounds isolated from 4:1 (and 6:1) reaction solutions feature Th monomers linked by MO4 –, the 3:1 reaction solution yielded the well-known dihydroxide-bridged thorium dimer, linked, and capped by MO4 –. Density functional theory calculations on ReO4 –/TcO4 – isomorphs suggest similar bonding characteristics in the solid state, but experimental solution characterization noted differences. Specifically, small-angle X-ray scattering studies suggest the bonding of Th–TcO4 – persists in solution, while Th–ReO4 – bonding is less apparent.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions

et al. 2023

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“…31 It must be accentuated here that Zr(IV) and Pd(II) do not get extracted feasibly by 1.1 M TBP/n-DD under HLLW feed condition (3-4 M nitric acid). [32][33][34] Though T2EHDGA can extract these fission products appreciably, it requires the presence of TBP to avoid third-phase formation (vide supra). gradually with an increase in Zr(IV) concentration, while a reverse trend was observed in the case of Pd(II).…”

Section: Effect Of Tbp Concentration On Nitric Acid and Eu(iii) Loadingmentioning

confidence: 99%

Understanding the correlation between extraction and luminescence behavior of Eu(iii) in a biphasic system in the presence of Co-extracting metal ions

Rout,

Kumar,

Ramanathan

2023

New J. Chem.

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“…4 Modified PUREX methods, for example, the uranium extraction (UREX) process, have been developed over time to target different end goals, such as limiting proliferation risks or separating additional risk-driving radionuclides. 4 In both UREX and PUREX, technetium has been observed to coextract with U(VI) and Pu(IV), 5 yet the molecular-level understanding of this coextraction process is limited. This hampers efficient separation of targeted species and demands cumbersome modification of commonly used extraction processes, such as the separation of U(VI) and Tc(VII) via anion exchange.…”

Section: ■ Introductionmentioning

confidence: 99%

Plutonium and Cerium Perrhenate/Pertechnetate Coordination Polymers and Frameworks

Shohel,

Sockwell,

Hixon

et al. 2024

Inorg. Chem.

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Spent nuclear fuel (SNF) contains transuranic and lanthanide species, which are sometimes recovered and repurposed. One particularly problematic fission product, 99 TcO 4 − , hampers this recovery via coextraction with high valence metals, perhaps by complexation during aqueous reprocessing of SNF. There is limited molecular-level knowledge concerning the coordination chemistry between TcO 4 − or its well-known surrogate ReO 4 − and transuranic/lanthanide species. In the current study, we investigated the coordination of ReO 4 − /TcO 4 − with plutonium and cerium cations by structural and chemical characterization of a series of isolated extended solids. In this study, Ce represents both trivalent lanthanides and is considered a surrogate for Pu, respectively, in its common trivalent and tetravalent oxidation states. The structural elucidation of the seven isolated crystalline solids revealed that ReO 4 − /TcO 4 − directly connects to Pu IV , Pu VI O 2 2+ , Ce III , and Ce IV in the terminal and bridging coordination modes, leading to 1-, 2-, and 3-dimensional frameworks. For example, ReO 4 − coordination to Pu(IV) formed a 1D chain or 2D framework, isostructural with previously isolated Th(IV) compounds. However, Pu VI O 2 2+ alternating with ReO 4 − led to a unique 1D chain, different from the prior-reported U(VI)/Np(VI)-ReO 4 − /TcO 4 − structures. Coordination of ReO 4 − /TcO 4 − with Ce(III) promotes the assembly of 3D frameworks. Finally, attempted synthesis of a Ce(IV)-ReO 4− compound resulted in a 2D framework with a mixed-valence Ce III/IV . The highly acidic reaction conditions supported the reduction of both Ce IV and Tc VII , challenging isolation of compounds featuring these species. Only one TcO 4 -containing structure was obtained in this study (Ce III −TcO 4 3D framework), vs the six total Ce/Pu-ReO 4 compounds. Our three Pu-ReO 4 crystal structures are the first reported and translated to atomic-level information about Pu-TcO 4 coordination in nuclear fuel reprocessing scenarios, in addition to broadening our knowledge of bonding trends in the early, high-valence actinides.

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A review of technetium and zirconium extraction into tributyl phosphate in the PUREX process

Cited by 33 publications

References 73 publications

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions

Understanding the correlation between extraction and luminescence behavior of Eu(iii) in a biphasic system in the presence of Co-extracting metal ions

Plutonium and Cerium Perrhenate/Pertechnetate Coordination Polymers and Frameworks

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A review of technetium and zirconium extraction into tributyl phosphate in the PUREX process

Cited by 33 publications

References 73 publications

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO4 and Th–ReO4 Frameworks and Solutions

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO4 and Th–ReO4 Frameworks and Solutions

Understanding the correlation between extraction and luminescence behavior of Eu(iii) in a biphasic system in the presence of Co-extracting metal ions

Plutonium and Cerium Perrhenate/Pertechnetate Coordination Polymers and Frameworks

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Product

Resources

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Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions

Elucidating Actinide–Pertechnetate and Actinide–Perrhenate Bonding via a Family of Th–TcO₄ and Th–ReO₄ Frameworks and Solutions