Medical RI production in existing reactors, 2; Optimization of neutron spectrum field for Mo/Tc production in the experimental fast reactor Joyo

Sasaki, Yuto*; Iwahashi, Daiki*; Maeda, Shigetaka   ; Takaki, Naoyuki*

Mo-99 (half-life: 66 hours) / Tc-99m (half-life: 6 hours), which is the most sought after RI for diagnosis, is 100% dependent on imports. Therefore, domestic production is expected due to the instability of supply due to the deterioration of overseas manufacturing reactors and transportation troubles caused by natural disasters, and discussions are becoming active in the RI expert subcommittee. In this study, we investigated a method for efficiently producing Mo-99 by the neutron capture reaction of Mo-98 utilizing the neutron deceleration field around the core of the high-speed experimental reactor "Joyo". Specifically, a parameter survey was conducted on the core configuration, target loading position, deceleration aggregate material and its filling ratio, etc., and the most efficient core configuration was clarified.