First nuclear transmutation of 237Np and 241Am by accelerator-driven system at Kyoto University Critical Assembly

• Published in: Journal of nuclear science and technology 2019-08, Vol.56 (8), p.684-689
• Main Authors: Cheol Ho Pyeon, Yamanaka, Masao, Oizumi, Akito, Fukushima, Masahiro, Chiba, Go, Watanabe, Kenichi, Endo, Tomohiro, Van Rooijen, Wilfred G, Hashimoto, Kengo, Sakon, Atsushi, Aizawa, Naoto, Kuriyama, Yasutoshi, Uesugi, Tomonori, Ishi, Yoshihiro
• Format: Article
• Language: English
• Subjects: Americium; Americium 241; Assembly; Bismuth; Foils; Neptunium isotopes; Proton accelerators; Transmutation; Uranium
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/00223131.2019.1618406

This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (237Np) and americium-241 (241Am), and capture reactions of 237Np. Subcritical irradiation of 237Np and 241Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (237Np or 241Am) and reference (uranium-235) foils. The first nuclear transmutation of 237Np and 241Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.