Evaluation of the production amount of ²²⁵Ac and its uncertainty through the ²²⁶Ra(n,2n) reaction in the experimental fast reactor Joyo

²²⁵Ac is a promising nuclide for targeted alpha therapy. At present, the nuclide is mainly extracted from ²²⁹Th generators, but its total radioactivity of the world is only 63 GBq/y. Therefore, it is unclear whether this method alone can meet future global medical demand. In this study, we analyzed the production amount of ²²⁵Ac and its uncertainty due to the neutron flux and nuclear reaction cross-sections while analyzing the generation process of ²²⁵Ac using the experimental fast reactor Joyo operated by the Japan Atomic Energy Agency (JAEA). The analysis showed that irradiating 1 g of ²²⁶Ra for 45 d at the core center of Joyo can produce 15.4 ± 6.2 GBq of ²²⁵Ac. Therefore, with six irradiations per year (45 d x 6 = 270 d/year), Joyo can produce 55.3 to 129.1 GBq of ²²⁵Ac, equivalent to 86 to 200% of the current world supply. (author)