Structural investigation of thorium in molten lithium–calcium fluoride mixtures for salt treatment process in molten salt reactor

Numakura, Masahiko; Sato, Nobuaki; Bessada, Catherine; Okamoto, Yoshihiro; Akatsuka, Hiroshi; Nezu, Atsushi; Shimohara, Yasuaki; Tajima, Kazuo; Kawano, Hirokazu; Nakahagi, Takeshi; Matsuura, Haruaki

doi:10.1016/j.pnucene.2011.04.026

Cited by 16 publications

(6 citation statements)

References 17 publications

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“…The comparison between ZrF 4 -LiF and ThF 4 -LiF systems (Figure 6), at 20°C above the melting point and at the same composition range in ThF 4 , shows that the average zirconium environment (7 F -) is different from thorium one (8 F -) in the molten state, whereas the two tetravalent ions have the same coordination in the solid state (8 F -). This difference was already evidenced by Numakura et al [43] and attributed to the difference of ionic radii of both cations (r Th =1.05 Å and r Zr =0.84 Å [44] for a coordination number of 8).…”

Section: Molten Mf-thf 4 Systems (M=li Na K)mentioning

confidence: 54%

Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

Bessada

Zanghi

Salanne

et al. 2020

Journal of Molecular Liquids

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This article focuses on the speciation of molten fluoride mixtures based on ThF 4 and UF 4 actinides used in molten salt reactors. The local structure of molten AF-MF 4 systems (A=Li + , Na + , K + ; M= Th 4+ , U 4+ ) was studied in situ by combining measurements by high temperature X-ray absorption spectroscopy and molecular dynamics simulations. In the molten state, 20°C higher than the melting temperature, these mixtures are composed of free fluorine and anionic species [MF 7 ] 3-, [MF 8 ] 4and [MF 9 ] 5whose distribution varies with the amount of MF 4 (M= Th 4+ , U 4+ ). Regardless of the cation, these complexes consist of an average of 8 Fneighbors for MF 4 content is less than 35 mol. %. This value decreases to 7 as the size of the alkaline ion A (A=Li + , Na + , K + ) increases. The [MF x ] 4-x species are linked together by bridging fluorine ions to form long chains [M x F Y ] 4x-y . The addition of a few percent UF 4 to the eutectic LiF-ThF 4 composition (77.5 mol% -22.5 mol. %) at 700°C leads to a slight increase in the population of free fluorine ions due to the breakdown of the Th-F links to form complexes [UF x ] 4-x isolated or connected to the (Th x F y ) 4x-y chains. This change in the structure of the liquid results in a slight decrease in viscosity when a few mol. % of UF 4 is added.

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Section: Molten Mf-thf 4 Systems (M=li Na K)mentioning

confidence: 54%

Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

Bessada

Zanghi

Salanne

et al. 2020

Journal of Molecular Liquids

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“…However, they gave no further structural information. The structural information of ThF 4 in LiF‐CaF 2 melt was studied more systematically by Numakura et al and Matsuura et al The EXAFS measurements of different proportion ternary mixtures at various temperatures showed that the distance between Th 4+ and F − was 2.33–2.34 Å and the coordination number was 9. Matsuura et al further studied the EXAFS of molten x ThF 4 – (1‐ x ) MF (M = Li, Na or Ca, 0 < x < 1) in mono‐ and di‐valent cationic fluoride mixtures.…”

Section: Determination Of Actinide Speciation By Xafsmentioning

confidence: 99%

Exploring Actinide Materials Through Synchrotron Radiation Techniques

et al. 2014

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Synchrotron radiation (SR) based techniques have been utilized with increasing frequency in the past decade to explore the brilliant and challenging sciences of actinide‐based materials. This trend is partially driven by the basic needs for multi‐scale actinide speciation and bonding information and also the realistic needs for nuclear energy research. In this review, recent research progresses on actinide related materials by means of various SR techniques were selectively highlighted and summarized, with the emphasis on X‐ray absorption spectroscopy, X‐ray diffraction and scattering spectroscopy, which are powerful tools to characterize actinide materials. In addition, advanced SR techniques for exploring future advanced nuclear fuel cycles dealing with actinides are illustrated as well.

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“…10, we can conclude that the most stable complexes of LiF-ThF 4 are ThF 6 2-, ThF 7 3− and ThF 8 4− . Some work has already done by NMR technique thanks to Bessada and Numakura showed also the number of fluorides is 7-8 around thorium [22,23].…”

Section: Mathematical Analysis Of Th(iv)/th Equilibrium Potential Evomentioning

confidence: 99%

Electrochemistry of thorium fluoride in LiCl-KCl eutectic melts and methodology for speciation studies with fluorides ions

Delpech

Jaskierowicz

Rodrigues

2014

Electrochimica Acta

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Structural investigation of thorium in molten lithium–calcium fluoride mixtures for salt treatment process in molten salt reactor

Cited by 16 publications

References 17 publications

Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

Exploring Actinide Materials Through Synchrotron Radiation Techniques

Electrochemistry of thorium fluoride in LiCl-KCl eutectic melts and methodology for speciation studies with fluorides ions

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