Processing used nuclear fuel with nanoscale control of uranium and ultrafiltration

Wylie, Ernest M.; Peruski, Kathryn; Prizio, S.; Bridges, Andrea N.A.; Rudisill, Tracy S.; Hobbs, D.T.; Phillip, William A.; Burns, Peter C.

doi:10.1016/j.jnucmat.2016.02.013

Cited by 30 publications

(39 citation statements)

References 25 publications

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“…Figure also shows SAXS analysis of the aqueous phase, the clusters extracted into the organic phase, and the simulated U 32 . While clusters likewise form from SIMFUEL (as observed previously) and they transfer to the kerosene layer, there are some differences between the aqueous‐ and organic‐phase clusters, as discussed and elucidated below.…”

Section: Resultssupporting

confidence: 53%

“…For experiments performed by using SIMFUEL as a starting material, we suspended the SIMFUEL powder (50 mg) in water (0.6 mL), ammonium hydroxide (0.4 mL, 4 m ), and hydrogen peroxide (0.3 mL, 30 %), adapting the procedure from the prior study of Burns, who demonstrated filtration separation of uranium from the minor oxides in SIMFUEL . The majority of the UO 2 was rapidly oxidized, yielding a light brown (black and yellow mixed) suspension.…”

Section: Methodsmentioning

confidence: 99%

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Benchmarking Uranyl Peroxide Capsule Chemistry in Organic Media

et al. 2016

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Uranyl peroxide capsules are a recent addition to polyoxometalate (POM) chemistry. Ten years of development has ensued only in water, while transition metal POMs are commonly exploited in aqueous and organic media, controlled by counterions or ligation to render the clusters hydrophilic or hydrophobic. Here, new uranyl POM behavior is recognized in organic media, including (1) stabilization and immobilization of encapsulated hydrophilic countercations, identified by Li nuclear magnetic resonance (NMR) spectroscopy, (2) formation of new cluster species upon phase transfer, (3) extraction of uranyl clusters from different starting materials including simulated spent nuclear fuel, (4) selective phase transfer of one cluster type from a mixture, and (5) phase transfer of clusters from both acidic and alkaline media. The capsule morphology of the uranyl POMs renders accurate characterization by X‐ray scattering, including the distinction of geometrically similar clusters. Compositional analysis of the aqueous phase post‐extraction provided a quantitative determination of the ion exchange process that enables transfer of the clusters into the organic phase. Preferential partitioning of uranyl POMs into organic media presents new frontiers in metal ion behavior and chemical reactions in the confined space of the cluster capsules in hydrophobic media, as well as the reactivity of clusters at the organic/aqueous interface.

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Section: Resultssupporting

confidence: 53%

Section: Methodsmentioning

confidence: 99%

Benchmarking Uranyl Peroxide Capsule Chemistry in Organic Media

et al. 2016

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“…[3][4][5][6][7][8] Among these clusters is one that comprises 60 uranyl moieties and bears a remarkable resemblance to the prototypical nanostructure buckminsterfullerene, C 60 . 9 Uranium oxide nanostructure materials are of interest for potential relevance to advanced nuclear technology, including processing 10 and degradation 11 of nuclear fuels. There is fundamental interest in understanding the driving forces for the formation of the bent uranyl peroxide cage nanostructures, and the nature of the bonding in them.…”

Section: -mentioning

confidence: 99%

A Uranyl Peroxide Dimer in the Gas Phase

Dau

Rao

et al. 2017

Inorg. Chem.

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The gas-phase uranyl peroxide dimer, [(UO)(O)(L)] where L = 2,2'-trifluoroethylazanediyl)bis(N,N'-dimethylacetamide), was synthesized by electrospray ionization of a solution of UO and L. Collision-induced dissociation of this dimer resulted in endothermic O atom elimination to give [(UO)(O)(L)], which was found to spontaneously react with water via exothermic hydrolytic chemisorption to yield [(UO)(OH)(L)]. Density functional theory computations of the energies for the gas-phase reactions are in accord with observations. The structures of the observed uranyl dimer were computed, with that of the peroxide of particular interest, as a basis to evaluate the formation of condensed phase uranyl peroxides with bent structures. The computed dihedral angle in [(UO)(O)(L)] is 145°, indicating a substantial deviation from the planar structure with a dihedral angle of 180°. Energies needed to induce bending in the most elementary gas-phase uranyl peroxide complex, [(UO)(O)], were computed. It was found that bending from the lowest-energy planar structure to dihedral angles up to 140° required energies of <10 kJ/mol. The gas-phase results demonstrate the inherent stability of the uranyl peroxide moiety and support the notion that the uranyl-peroxide-uranyl structural unit is intrinsically planar, with only minor energy perturbations needed to form the bent structures found in studtite and uranyl peroxide nanostructures.

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“…They are known for their formation by self-assembly, structural diversity, as well as their wide-ranging potential and realized applications including but not limited to catalysis, sustainable energy, electronics, and sensors . Relatively recently discovered actinide POMs also have potential applications in recycling nuclear fuels , and fabrication of mixed oxide fuels . POMs are valuable models for studying structure-size-property relations such as aggregation behavior in solution because they are larger than most inorganic complexes but smaller than colloids and are dissolvable as macroanions in various solvents .…”

Section: Introductionmentioning

confidence: 99%

Reactivity, Formation, and Solubility of Polyoxometalates Probed by Calorimetry

et al. 2020

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Room temperature calorimetry methods were developed to describe the energy landscapes of six polyoxometalates (POMs), Li-U24, Li-U28, K-U28, Li/K-U60, Mo132, and Mo154, in terms of three components: enthalpy of dissolution (ΔHdiss), enthalpy of formation of aqueous POMs (ΔHf,(aq)), and enthalpy of formation of POM crystals (ΔHf,(c)). ΔHdiss is controlled by a combination of cation solvation enthalpy and the favorability of cation interactions with binding sites on the POM. In the case of the four uranyl peroxide POMs studied, clusters with hydroxide bridges have lower ΔHf,(aq) and are more stable than those containing only peroxide bridges. In general for POMs, the combination of calorimetric results and synthetic observations suggest that spherical topologies may be more stable than wheel-like clusters, and ΔHf,(aq) can be accurately estimated using only ΔHf,(c) values owing to the dominance of the clusters in determining the energetics of POM crystals.

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Processing used nuclear fuel with nanoscale control of uranium and ultrafiltration

Cited by 30 publications

References 25 publications

Benchmarking Uranyl Peroxide Capsule Chemistry in Organic Media

Benchmarking Uranyl Peroxide Capsule Chemistry in Organic Media

A Uranyl Peroxide Dimer in the Gas Phase

Reactivity, Formation, and Solubility of Polyoxometalates Probed by Calorimetry

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