Mechanics and Heat Transfer Design of Thorium Metal Target Protection Thin Film in Isotope Production in Gansu Province

Isotopes are important strategic materials, and are irreplaceable and central to the fields of national defence, energy security, medical health, and scientific research. With the demonstrated efficacy of targeted alpha therapy using 225 Ac, there is a pressing need to explore radiopharmaceuticals capable of delivering consistent and ample quantities of 225 Ac. Isotope production in Gansu Province has initiated the production of 225 Ac via bombardment of thorium metal with 480 MeV protons. To ensure the stability and safety of thorium targets under high-power beam conditions, this study proposes a novel packaging design for the protective layer of thorium targets, accompanied by detailed mechanical and thermal analyses. The study employs an Inconel 718 alloy as the film material for vacuum welding packaging, and simulates local displacement variations in the Inconel 718 film under different thicknesses, lengths, gaps, and flange fillet conditions. The optimal parameter settings that meet the design requirements are then determined. Additionally, beam energy deposition is assessed using Monte Carlo N-Particle (MCNP 6) neutron calculation software, while the heat transfer process is simulated with Fluent software to optimize the cooling mechanism, ensuring the stability and safety of the target material. The final design provides a theoretical foundation for isotope production targets in Gansu Province.