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Kaneda-Nakashima, Kazuko*; Shirakami, Yoshifumi*; Kadonaga, Yuichiro*; Watabe, Tadashi*; Oe, Kazuhiro*; Yin, X.*; Haba, Hiromitsu*; Shirasaki, Kenji*; Kikunaga, Hidetoshi*; Tsukada, Kazuaki; et al.
International Journal of Molecular Sciences (Internet), 25(2), p.933_1 - 933_14, 2024/01
Times Cited Count：1 Percentile：95.46(Biochemistry & Molecular Biology)Arai, Masaji; Maeda, Shigetaka
Rinsho Hoshasen, 68(10), p.963 - 970, 2023/10
Ac-225 is attracting attention as an alpha-emitting medical radioisotope. Since its demand is expected to increase, domestic production of Ac-225 is required from the viewpoint of Japan's medical research and economic security. To establish the technical bases for the Ac-225 production, JAEA has evaluated the radioactivity that can be produced in the experimental fast reactor Joyo and designed the concept that upgrades the existing facilities for transporting the irradiated target from Joyo to a neighboring PIE facility rapidly. Efficient Actinium-225 Separation from Ra-226 irradiated in a fast reactor was studied. This study has revealed that Joyo can sufficiently produce Ac-225 as a raw material for pharmaceuticals.
Maeda, Shigetaka
no journal, ,
The objectives of this study are a production of Actinium-225 in Japan, and the use of the experimental fast reactor, Joyo. In this concept study, the technical bases of the production should be established. This concept study shows that the experimental fast reactor Joyo can produce a sufficient amount of Ac-225. This has been confirmed by calculation. The existing refueling and PIE transfer systems with some modifications can quickly transfer irradiated Ra-226 to the neighboring PIE facility. We have completed the concept design for the modifications. Issues and challenges are procuration of Ra-226, Joyo restart, for which we need take measures to meet the new regulations of NRA, Japan, licensing for RI use, production, and disposal, and, demonstration of Ac-225 production in Joyo.
Iwahashi, Daiki*; Sasaki, Yuto*; Maeda, Shigetaka; Takaki, Naoyuki*
no journal, ,
Ac-225 is attracting attention as a radioisotope for targeted 
-therapy (TAT) used for the treatment of prostate cancer and the like. Therefore, we investigated a method of loading Ra-226 into the fast reactor Joyo and producing Ac-225 by transmutation. Ac-225 production can be expected by the (n,2n) reaction using fast neutrons in the center of the core and the (3n,
) reaction using thermalized neutrons in the reflector region.
Ouchi, Kazuki; Kitatsuji, Yoshihiro; Maeda, Shigetaka; Takaki, Naoyuki*
no journal, ,
In previous study, we have studied the purification process for efficient recovery of Ac-225 produced by neutron irradiation of Ra-226 in a fast reactor. In this presentation, the reuse process for re-irradiating Ra-226 after separation of Ac-225 was studied by using Ba and La as alternative elements. By using Ln resin as adsorbent and changing the nitric acid concentration, the conditions under which Ra can be isolated from impurities expected to be produced by irradiation were clarified. We propose a purification process for Ac using DGA resin and a recycling process for Ra using Ln resin.
Sasaki, Yuto; Sano, Aaru; Itagaki, Wataru; Maeda, Shigetaka; Takaki, Naoyuki*
no journal, ,
no abstracts in English
Maeda, Shigetaka
no journal, ,
Ac is attracting attention as an alpha-emitting medical radioisotope. Since its demand is expected to increase, domestic production of Ac is required from the viewpoint of Japan's medical research and economic security. In this presentation, we report on domestic and international efforts, JAEA's efforts, the conceptual study of production using the 
Ra and 
Th irradiation methods at the experimental fast reactor Joyo, and evaluation of production amount. In particular, we report on the most probable value and uncertainty evaluations using the Monte Carlo calculation code MCNP, which was established through the past neutron dosimetry examination in Joyo.
Maeda, Shigetaka
no journal, ,
Regarding Actinium-225, which is one of the medical radioisotopes and has been attracting attention today, we will report on the domestic movement toward domestic production, the research and development plan and progress for production of Actinium-225 using the experimental fast reactor Joyo.
