This paper investigates the parameters of aerosol particles that occur in the course of spontaneous vapor thermal condensation and bubbling of the saline blend in 66 LiF-34 BeF2 eutectic compound (mol %) with helium in the vertical-bubbles flow mode in an ampoule device to create medical reactor radioisotopes produced at a temperature of T ≈ 900K. The aerosols mass entrainment and chemical composition have been measured. This paper also shows that the aerosol particle-size distribution is bimodal and the particles’ mass concentration substantially exceeds the maximum permissible concentration (MPC). Moreover, the characteristics of the recovered multi-layer nickel-made nano-filters intended for aerosols’ ultrahigh filtering from a liquid molten salt are studied.