  The structure of the molten salt (LiF)$_{0.465}$(NaF)$_{0.115}$(KF)$_{0.42}$
(FLiNaK), a potential coolant for molten salt nuclear reactors, has been
studied by ab initio molecular dynamics simulations and neutron total
scattering experiments. We find that the salt retains well-defined short-range
structural correlations out to approximately 9 Angstroms at typical reactor
operating temperatures. The experimentally determined pair distribution
function can be described with quantitative accuracy by the molecular dynamics
simulations. These results indicate that the essential ionic interactions are
properly captured by the simulations, providing a launching point for future
studies of FLiNaK and other molten salts for nuclear reactor applications.
