Print Email Facebook Twitter New insights and coupled modelling of the structural and thermodynamic properties of the LiF-UF4 system Title New insights and coupled modelling of the structural and thermodynamic properties of the LiF-UF4 system Author Ocadiz flores, J.A. (TU Delft RST/Reactor Physics and Nuclear Materials) Gheribi, A. E. (Polytechnique Montreal) Vlieland, J. (TU Delft RST/Technici Pool) Dardenne, K. (Karlsruhe Institut für Technologie) Rothe, J. (Karlsruhe Institut für Technologie) Konings, R. (TU Delft RST/Reactor Physics and Nuclear Materials; European Commission Joint Research Centre, Institute for Transuranium Elements Karlsruhe) Smith, A.L. (TU Delft RST/Reactor Physics and Nuclear Materials) Date 2021 Abstract © 2021 The Authors LiF-UF4 is a key binary system for molten fluoride reactor technology, which has not been scrutinized as thoroughly as the closely related LiF-ThF4 system. The phase diagram equilibria in the system LiF-UF4 are explored in this work with X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The short-range ordering in the molten salt solution is moreover surveyed with Extended X-ray Absorption Fine Structure spectroscopy (EXAFS) and interpreted using a combination of standard fitting of the EXAFS data and Molecular Dynamics (MD) simulations with a Polarizable Ion Model (PIM) potential. The density, excess molar volume, thermal expansion, heat capacity, and enthalpy of mixing are extracted from the MD simulations across a range of temperatures and compositions; the behavior is non-ideal, with reasonably good agreement with the experimental data. Also calculated is the distribution of heteropolyanions in the liquid solution, and modelled using the quasi-chemical formalism in the quadruplet approximation taking into account the existence of the single-shell complexes [UF7]3−, [UF8]4−, and the dimeric species [U2F14]6−. Subjecting the optimization of the excess Gibbs energy parameters of the liquid solution to the constraints of the phase diagram data and local structure of the melt as derived from the EXAFS and coupled MD simulations, a CALPHAD-type assessment is proposed, linking structural and thermodynamic properties, with a rigorous physical description of the melt. Subject CALPHADDifferential scanning calorimetryEXAFSMolten salt reactorPolarizable ion model (PIM)X-ray diffraction To reference this document use: http://resolver.tudelft.nl/uuid:75756af2-e2bb-49bc-a1b2-47f0ae9d9747 DOI https://doi.org/10.1016/j.molliq.2021.115820 ISSN 0167-7322 Source Journal of Molecular Liquids, 331 Part of collection Institutional Repository Document type journal article Rights © 2021 J.A. Ocadiz flores, A. E. Gheribi, J. Vlieland, K. Dardenne, J. Rothe, R. Konings, A.L. Smith Files PDF 1_s2.0_S0167732221005456_main.pdf 2.38 MB Close viewer /islandora/object/uuid:75756af2-e2bb-49bc-a1b2-47f0ae9d9747/datastream/OBJ/view