A study of plutonium fluoride solubility in LiF–BeF2 melt for the substantiation of a molten salt reactor for Np, Am, Cm transmutation

The paper presents a justification, setting, and results of experiments on the determination of the liquidus temperature for a molten salt comprised of 73LiF–27BeF₂ with plutonium trifluoride, considered as the fuel circuit salt of a liquid-salt reactor for burning Np, Am, Cm. The liquidus temperature of the melt was determined using a differential scanning calorimetry method; the plutonium concentration in the samples was controlled by recording the γ‑radiation of plutonium isotopes. According to the results of the studies, the liquidus temperature comprised 600–680 °C across a range of plutonium trifluoride concentrations from 0.1–3 mol.%. According to the performed calculations, in order to transmute 250 kg/year of Np, Am, Cm in an MSR‑T reactor, this restriction on the concentration of actinide fluorides in the fuel salt at its operating temperature in the reactor of 650–750 °C requires 550–660 kg/year of plutonium.