Evidence of dynamical local scale distribution heterogeneities in CsF-AF (A=Li, Na, K and Rb) molten salts

Rollet, Anne‐Laure; Bessada, Catherine

doi:10.1016/j.jfluchem.2015.08.020

Cited by 2 publications

(6 citation statements)

References 80 publications

(73 reference statements)

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“…As such, even small amounts of Cs could affect the liquid structure. Experimentally, NMR measurements of CsF–LiF mixtures seem to confirm the expected enhancement of Li clustering due to the size mismatch of Li and Cs ions . Previous neutron diffraction measurements in FLiNaK did not have the resolution to reach 1 Å –1 , while our measurements did.…”

Section: Introductionsupporting

confidence: 70%

“…Experimentally, NMR measurements of CsF−LiF mixtures seem to confirm the expected enhancement of Li clustering due to the size mismatch of Li and Cs ions. 19 Previous neutron diffraction measurements in FLiNaK did not have the resolution to reach 1 Å −1 , 13 while our measurements did. Thus, we probed the medium-range order and the effect of Cs on the structure of FLiNaK directly but did not find an enhancement of Li clustering.…”

Section: Introductioncontrasting

confidence: 53%

“…This number is significantly larger than that deduced from NMR measurements in CsF−LiF mixtures. 19 The discrepancy is likely the effect of an admixture of progressively larger Na and K ions. Also, the coordination of Cs in solid and molten CsF is close to 6, 49 while in solid CsLiF 2 , Cs is bonded to 8 F atoms.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Molecular Structure and Phase Equilibria of Molten Fluoride Salt with and without Dissolved Cesium: FLiNaK–CsF (5 mol %)

Sprouster

Zheng

Lee

et al. 2022

ACS Appl. Energy Mater.

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We demonstrate effects of Cs ions on the melting transition and molecular structure of molten FLiNaK (a eutectic mixture of LiF–NaF–KF). FLiNaK is a commonly studied multicomponent model system, which represents the physical and chemical behavior of fluoride salts for nuclear energy applications. Dissolution of nuclear fuels leads to the formation of fission products directly in the molten salt. Cs is one of the most important fission products, due to its relative abundance, long half-life, and potential environmental and health effects. Here, we determine the molecular structure and phase equilibria of dissolved Cs in FLiNaK by a combination of X-ray diffraction, X-ray total scattering, ab initio molecular-dynamics calculations, and computational thermodynamics. Although Cs ions have a relatively large size, we did not find significant evidence that they disrupt the existing molecular structure of the liquid. We found good agreement between our simulated and measured structure factors and calculated that the coordination number of Cs is close to 10. X-ray diffraction in combination with computational thermodynamics demonstrates that upon freezing Cs ions are captured into a CsLiF2 compound, with a lower melting temperature than that of the FLiNaK mixture and a much higher temperature than that predicted for CsLiF2 by computational thermodynamics. We also demonstrated a novel sample environment that we developed to X-ray measurements of molten fluoride or fuel salts.

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Section: Introductionsupporting

confidence: 70%

Section: Introductioncontrasting

confidence: 53%

See 1 more Smart Citation

Molecular Structure and Phase Equilibria of Molten Fluoride Salt with and without Dissolved Cesium: FLiNaK–CsF (5 mol %)

Sprouster

Zheng

Lee

et al. 2022

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

show abstract

“…Experimentally, NMR measurements of CsF-LiF mixtures seem to confirm the expected enhancement of Li clustering due to the size mismatch of Li and Cs ions. 19 Previous neutron di↵raction measurements in FLiNaK did not have the resolution to reach 1 Å 1 , 13 while our measurements did. Thus, we probed the medium-range order and the e↵ect of Cs on the structure of FLiNaK directly but did not find an enhancement of Li clustering.…”

Section: Introductionmentioning

confidence: 53%

“…This number is significantly larger than that deduced from NMR measurements in CsF-LiF mixtures. 19 The discrepancy is likely the e↵ect of admixture of progressively larger Na and K ions. Also, the coordination of Cs in solid and molten CsF is close to 6, 48 while in solid CsLiF 2 , Cs is bonded to 8 F atoms.…”

Section: Discussionmentioning

confidence: 99%

The molecular structure and phase equilibria of molten fluoride salt with and without dissolved cesium: FLiNaK-CsF (5 mol%)

Sprouster

Zheng

Lee

et al. 2022

Preprint

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We demonstrate effects of Cs ions on the melting transition and molecular structure of molten FLiNaK (a eutectic mixture of LiF-NaF-KF). FLiNaK is a commonly studied multi-component model system, which represents the physical and chemical behavior of fluoride salts for nuclear energy applications. Dissolution of nuclear fuels leads to the formation of fission products directly in the molten salt. Cs is one of the most important fission products, due to its relative abundance, long half life, and potential environmental and health effects. Here, we determine the molecular structure and phase equilibria of dissolved Cs in FLiNaK by a combination of X-ray diffraction, X-ray total scattering, ab initio molecular dynamics calculations, and computational thermodynamics. Although Cs ions have a relatively large size, we did not find significant evidence that they disrupt the existing molecular structure of the liquid. We found good agreement between our simulated and measured structure factors, and calculated that the coordination number of Cs is close to 10. X-ray diffraction in combination with computational thermodynamics demonstrates that upon freezing Cs ions are captured into a CsLiF2 compound, with a lower melting temperature than the FLiNaK mixture and much higher than that predicted for CsLiF2 by computational thermodynamics. We also demonstrated a novel sample environment that we developed to X-ray measurements of molten fluoride or fuel salts.

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Evidence of dynamical local scale distribution heterogeneities in CsF-AF (A=Li, Na, K and Rb) molten salts

Cited by 2 publications

References 80 publications

Molecular Structure and Phase Equilibria of Molten Fluoride Salt with and without Dissolved Cesium: FLiNaK–CsF (5 mol %)

Molecular Structure and Phase Equilibria of Molten Fluoride Salt with and without Dissolved Cesium: FLiNaK–CsF (5 mol %)

The molecular structure and phase equilibria of molten fluoride salt with and without dissolved cesium: FLiNaK-CsF (5 mol%)

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