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Aizawa, Kosuke; Ueki, Yoshitaka*
Proceedings of Specialist Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal-Hydraulics and Severe Accidents (SWINTH-2024) (USB Flash Drive), 7 Pages, 2024/06
Early detection of an anomaly greatly enhances the safety of nuclear power plants. A detection system called an acoustic measurement has high responsiveness, because sound produced by the anomaly is transmitted from the place at which an anomaly has occurred to a measurement point at a speed of sound, and the acoustic measurement has the potential to directly detect the physical quantity of an anomaly at its occurrence point. For sodium-cooled fast reactors, we have been developing an anomaly detection technique using the acoustic measurement that offers these features. This paper clarifies issues in applying the acoustic measurement to a sodium-cooled fast reactor, how we solve the issues, and the current status of this research.
Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki*
International Journal of Multiphase Flow, 171, p.104688_1 - 104688_13, 2024/01
Times Cited Count：2 Percentile：34.95(Mechanics)Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Proceedings of 17th International Heat Transfer Conference (IHTC-17) (Internet), 9 Pages, 2023/08
Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Journal of Sound and Vibration, 561, p.117797_1 - 117797_14, 2023/05
Times Cited Count：2 Percentile：48.35(Acoustics)Ueki, Yoshitaka*; Hashimoto, Shunsaku*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 5 Pages, 2023/05
Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
International Journal of Multiphase Flow, 159, p.104340_1 - 104340_8, 2023/02
Times Cited Count：7 Percentile：57.48(Mechanics)This study covers the accidental generation of bubble jet flow caused by steam generator (SG) tubes damaging in sodium cooled fast reactors (SFRs). The main objective of this study is to develop a novel state sensing method of bubble jet flow based on acoustic recognition and deep learning. Prior to the application of this method to actual SFRs, we utilize air and water as simulant fluids in order to perform the proof of concept. This study is divided into three phases. The first phase is the acquisition and analysis of pipe flow sound and bubble jet flow sound, each of which simulates the normal and anomaly sound from SG tubes in SFRs. The second phase is the preprocessing of acoustic signals and feature extraction. The third phase is the building of deep learning models and performance evaluation. As a result, every of our proposed models could distinguish between pipe flow sound and bubble jet sound with an accuracy of almost 100.00%, and the best model could classify pipe flow sound and three types of bubble jet flow sound with an accuracy of 99.76%. This result suggests that the acoustic recognition with deep learning has great potential to sense the state of bubble jet flow in actual SFRs.
113 of the 113th elementMorita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.
Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10
Times Cited Count：174 Percentile：97.27(Physics, Multidisciplinary)An isotope of the 113th element, 113, was produced in a nuclear reaction with a 
Zn beam on a 
Bi target. We observed six consecutive 
decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of 
Db and 
Lr both in decay energies and decay times. This indicates that the present decay chain consisted of 113, 
Rg (Z = 111), 
Mt (Z = 109), 
Bh (Z = 107), Db (Z = 105), and Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope 113, of the 113th element.
SO
/HNO
mixed solutionLi, Z.*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro; Sch
del, M.; Pershina, V.*; et al.
Radiochimica Acta, 100(3), p.157 - 164, 2012/03
Times Cited Count：14 Percentile：69.84(Chemistry, Inorganic & Nuclear)Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; Schdel, M.; et al.
Journal of Nuclear and Radiochemical Sciences, 11(1), p.7 - 11, 2010/06
The extraction behavior of rutherfordium (Rf) into trioctylphosphine oxide (TOPO) from 2.0 - 7.0 M HCl solution was studied together with that of the homologues Zr and Hf. The extracted yields of Rf, Zr, and Hf increased with an increase of HCl concentration, and the sequence of their extraction was Zr 
Hf 
Rf. It is suggested that the stability of the RfCl
2(TOPO) complex is lower than that of the corresponding species of the homologues.
Tsukada, Kazuaki; Haba, Hiromitsu*; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko*; Kasamatsu, Yoshitaka; Nishinaka, Ichiro; Ichikawa, Shinichi; Yasuda, Kenichiro; Miyamoto, Yutaka; et al.
Radiochimica Acta, 97(2), p.83 - 89, 2009/02
Times Cited Count：22 Percentile：79.39(Chemistry, Inorganic & Nuclear)Anion-exchange chromatography of element 105, dubnium (Db), produced in the 
Cm(
F, 5n)Db reaction is investigated together with the homologues Nb and Ta, and the pseudo-homologue Pa in 13.9 M hydrofluoric acid (HF) solution. The distribution coefficient (K
) of Db on an anion-exchange resin is successfully determined by running cycles of the 1702 chromatographic column separations. The result clearly indicates that the adsorption of Db on the resin is significantly different from that of the homologues and that the adsorption of anionic fluoro complexes of these elements decreases in the sequence of Ta 
Nb Db Pa.
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 43(3), p.219 - 220, 2001/03
no abstracts in English
Sakurai, Kiyoshi; Kume, Etsuo; Yatabe, Shigeru*; Maekawa, Fujio; Yamamoto, Toshihiro; Nagaya, Yasunobu; Mori, Takamasa; Ueki, Kotaro*; Naito, Yoshitaka*
JAERI-Review 2000-034, 133 Pages, 2001/02
JAERI-Review-2000-034.pdf:7.69MB
no abstracts in English
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(10), p.1048 - 1049, 2000/10
no abstracts in English
Sakurai, Kiyoshi; Kume, Etsuo; Yatabe, Shigeru*; Maekawa, Fujio; Yamamoto, Toshihiro; Nagaya, Yasunobu; Mori, Takamasa; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(10), p.1062 - 1065, 2000/10
no abstracts in English
Sakurai, Kiyoshi; Yamamoto, Toshihiro; Ueki, Kotaro*; Mori, Takamasa; Nomura, Yasushi; Naito, Yoshitaka*
Journal of Nuclear Science and Technology, 37(Suppl.1), p.446 - 448, 2000/03
no abstracts in English
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(2), p.114 - 115, 2000/02
no abstracts in English
Ueki, Yoshitaka*; Aizawa, Kosuke; Ara, Kuniaki*
no journal, ,
no abstracts in English
Ueki, Yoshitaka*; Hirako, Itsuki*; Aizawa, Kosuke; Ara, Kuniaki*
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Tezuka, Kosuke*; Ueki, Yoshitaka*; Aizawa, Kosuke; Ara, Kuniaki*
no journal, ,
Okumura, Shuya*; Ueki, Yoshitaka*; Aizawa, Kosuke; Ara, Kuniaki*
no journal, ,
