The local structure of nuclear molten salts with Cs impurities has not been measured by high-resolution total scattering. Low-resolution earlier measurements of molten CsCl provide a good point for comparison, 17,18 but there are significant structural di↵erences between binary and multi-component mixtures. In this paper, we report measurements and simulations of total and partial structure functions of molten FliNaK with and without added CsF. We chose to add 5 mol% of CsF in order to get measurable X-ray signal, although in working MSRs the concentration of Cs is likely to be about 1 mol%. (In previous studies, 1 and 3.3 mol% of CsF were added respectively. ) We found a good agreement between our AIMD and NNMD modeling and X-ray di↵raction experiments. This agreement gives us confidence in the modeling, which utilizes a novel fast-acting neural-network potential in Our measurement results in pure FLiNaK are in broad agreement with earlier measurements by X-ray and neutron di↵raction. 12,13 However, our measurements have much higher resolution especially in the low-Q region. Such resolution is necessary to validate simulations and uncover important details of the behavior of multiple ionic species in FLiNaK-CsF.