Multicomponent Diffusion in Molten Salt NaF-ZrF_4: Dynamical Correlations and Maxwell-Stefan Diffusivities

摘要

NaF-ZrF_4 is used as a waste incinerator and as a coolant in Generation IV reactors. Structural and dynamical properties of molten NaF-ZrF_4 system were studied along with Onsagercoefficients and Maxwell-Stefan (MS) Diffusivities applying Green-Kubo formalism and molecular dynamics (MD) simulations. The zirconium ions are found to be 8 fold coordinated with fluoride ions for all temperatures and concentrations. All the diffusive flux correlations show back-scattering. Even though the MS diffusivities are expected to depend very lightly on the composition because of decoupling of thermodynamic factor, the diffusivity D_(Na-F) shows interesting behavior with the increase in concentration of ZrF_4. This is because of network formation in NaF-ZrF_4. Positive entropy constraints have been plotted to authenticate negative diffusivities observed.