We request time on VESUVIO to study the properties of FLiBe using mass-resolved neutron spectroscopy (MANSE). FLiBe is a mixture of BeF2 and LiF and its physical properties in the liquid state resemble those of water. The low melting point of the eutectic mixture (630 K) makes it a promising solvent for molten-salt-reactor technologies, yet its microscopic properties under operating conditions remain largely unexplored. This proposal seeks to fill the above gap by providing direct and simultaneous access to the mean kinetic energies of all three nuclides. On the scientific front, these data will provide stringent benchmarks for first-principles calculations on this technologically relevant material. From an instrumentation point of view, these experiments will also serve to assess in detail current capabilities on VESUVIO to perform MANSE studies on ternary mixtures of light elements.