This study proposes a method for 99Mo production via electron accelerator irradiation of a natural–uranium–bearing liquid molten salt target, with advantages including low nuclear proliferation risk, online extraction capability, and low construction costs. The approach primarily produces 99Mo through photofission of uranium ( \(\sim \) 95%), specifically 238U( \(\gamma \) ,f). Secondary neutrons, originating from photonuclear interactions or fission processes, contribute minimally ( \(\sim \) 5%) to 99Mo production owing to their high energies and low fission cross sections. Key parameter analyses revealed that fluoride salt systems exhibit higher 99Mo yield. Their performance stems from high bremsstrahlung energy loss rate and superior photon yield, making them optimal molten salt target materials. To maximize photofission and photoneutron cross sections while minimizing high-energy gamma ray shielding requirements, an electron beam energy range of 40–80 MeV is recommended. To suppress local hot spots and prevent molten salt boiling, flow conditions were introduced to enhance convective heat transfer, effectively reducing the peak temperature. At a flow velocity of 0.5 m/s and under 80 MeV energy conditions, the maximum system temperature is only 808.9 K, which is significantly lower than the boiling point of 1773 K. Under optimized parameters, the maximum annual production capacity of 99Mo reaches 4486.49 Ci, sufficient for millions of diagnostic procedures and equivalent to 16.37% of China’s projected demand for 2030. This method provides a viable pathway for stable, large-scale 99Mo production.
