Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kikuchi, Shin; Sato, Rika; Kondo, Toshiki; Umeda, Ryota; Yamano, Hidemasa
Dai-28-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2024/06
no abstracts in English
Yamano, Hidemasa; Takano, Kazuya; Kurisaka, Kenichi; Kikuchi, Shin; Kondo, Toshiki; Umeda, Ryota; Sato, Rika; Shirakura, Shota*
Dai-28-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 5 Pages, 2024/06
This project studies investigation on safety design guideline and risk assessment technology for sodium-cooled fast reactor with the molten-salt heat storage system, development of evaluation method for heat transferring performance between sodium and molten-salt and improvement of the performance, and evaluation of chemical reaction characteristic between sodium and molten-salt and improvement of its safety. This paper describes the effect of sodium-molten salt heat transfer tube failure in addition to the project overview and progress.
Yomogida, Takumi; Hashimoto, Tadashi; Okumura, Takuma*; Yamada, Shinya*; Tatsuno, Hideyuki*; Noda, Hirofumi*; Hayakawa, Ryota*; Okada, Shinji*; Takatori, Sayuri*; Isobe, Tadaaki*; et al.
Analyst, 149(10), p.2932 - 2941, 2024/03
Times Cited Count：1 Percentile：52.96(Chemistry, Analytical)In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source to determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from the U mine. It is difficult to separate the fluorescent X-ray of the U L
line at 13.615 keV from that of the Rb K line at 13.395 keV in the X-ray fluorescence spectrum with an energy resolution of approximately 220 eV of the conventional silicon drift detector (SDD). Meanwhile, the fluorescent X-rays of U L and Rb K were fully separated by TES with 50 eV energy resolution at the energy of around 13 keV. The successful peak separation by TES led to an accurate mapping analysis of trace U in micro-X-ray fluorescence measurements and a decrease in the signal-to-background ratio in micro-X-ray absorption near edge structure spectroscopy.
-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samplesLi, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
Times Cited Count：10 Percentile：69.36(Chemistry, Analytical)no abstracts in English
Tsuji, Tomoyuki; Sugitsue, Noritake; Sato, Fuminori; Matsushima, Ryotatsu; Kataoka, Shoji; Okada, Shota; Sasaki, Toshiki; Inoue, Junya
Nihon Genshiryoku Gakkai-Shi ATOMO
, 62(11), p.658 - 663, 2020/11
no abstracts in English
Otaka, Toshiki*; Sato, Tatsumi*; Ono, Shimpei; Nagoshi, Kohei; Abe, Ryoji*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Nakatani, Kiyoharu*
Analytical Sciences, 35(10), p.1129 - 1133, 2019/10
Times Cited Count：9 Percentile：34.34(Chemistry, Analytical)Kiriyama, Hiromitsu; Suzuki, Masayuki*; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
Reza Kenkyu, 40(2), p.143 - 145, 2012/02
We demonstrate a compact, high-spatiotemporal-quality, high-intensity diode-pumped Yb:YAG thin-disk chirped-pulse amplification (CPA) laser system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). The stretched pulses are amplified in the OPCPA preamplifier and the following Yb:YAG main amplifier to 
100 mJ at 10 Hz. The broadband amplified beam quality of 1.1 (horizontal direction) and 1.4 (vertical direction) times diffraction limited and pulse compression down to 470 fs with contrast of better than 10
have been achieved successfully.
Watanabe, Gentaro*; Sonoda, Hidetaka*; Maruyama, Toshiki; Sato, Katsuhiko*; Yasuoka, Kenji*; Ebisuzaki, Toshikazu*
Physical Review Letters, 103(12), p.121101_1 - 121101_4, 2009/09
Times Cited Count：70 Percentile：89.93(Physics, Multidisciplinary)no abstracts in English
Ezure, Toshiki; Sato, Hiroyuki; Kimura, Nobuyuki; Kamide, Hideki
JAEA-Research 2008-093, 34 Pages, 2008/12
JAEA-Research-2008-093.pdf:10.5MB
Concerning the vortex cavitation in the sodium-cooled fast reactor, basic experiments were performed. The effects of pressure and viscosity on the inception of vortex cavitations were examined in a basic water experiments. As the results, it appeared that the onset value of cavitation coefficient became higher with the increase of the pressure. In addition, it also appeared that the onset value of cavitation coefficient became higher with lower viscosity. However, this difference of onset value for the viscosity became smaller with the increase pressure, and was negligible with the same pressure in the real reactor.
Sato, Hiroyuki; Ezure, Toshiki; Kamide, Hideki
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), P. 432, 2005/05
A compact sodium reactor is designed as a commercialized fast reactor cycle system. A 1/10th scaled water experiment was performed to optimize upper plenum flow in the reactor vessel, because of high flow velocity resulted from the compacted vessel. In the experiment, vortex cavitation was found at the hot leg inlet because of high velocity in the hot leg pipe (9.4m/s in the design). To evaluate inception cavitation condition of the commercialized reactor, we use the cavitation number k in order to consider the difference of system absolute pressures (0.1MPa in experiment and 0.3MPa in design). The minimum pressure at the vortex center will depend on vortex core radius (size of forced vortex region). It is related to axial velocity gradient and fluid viscosity in theory of the Burger's stretched vortex model. We carried out a basic water experiment to investigate the influence of system pressure and fluid viscosity on the vortex cavitation. The cavitation number at the inception of vortex cavitation slightly increased according to the increase of the system absolute pressure. It means that the vortex cavitation occurs easily under higher-pressure condition as compared with the similar condition of cavitation number with lower pressure. However the increase was less than 30% when the system pressure was varied from 0.1 to 0.3MPa. The influence of fluid viscosity was examined by change of fluid temperature. Velocity distribution around the vortex was also measured to see the structure of vortex.
Watanabe, Gentaro*; Maruyama, Toshiki; Sato, Katsuhiko*; Yasuoka, Kenji*; Ebisuzaki, Toshikazu*
Physical Review Letters, 94(3), p.031101_1 - 031101_4, 2005/01
Times Cited Count：93 Percentile：91.48(Physics, Multidisciplinary)no abstracts in English
Kotaki, Hideyuki; Kando, Masaki; Pirozhkov, A. S.; Kawase, Keigo*; Esirkepov, T. Z.; Fukuda, Yuji; Kiriyama, Hiromitsu; Okada, Hajime; Daito, Izuru; Kameshima, Takashi*; et al.
no journal, ,
no abstracts in English
Sato, Rika; Kondo, Toshiki; Umeda, Ryota; Kikuchi, Shin; Yamano, Hidemasa
no journal, ,
In a sodium-cooled fast reactor (SFR) coupled to thermal energy storage system, the reaction between nitrate molten salt as thermal storage material and sodium as coolant of SFR might occur under the postulated acccidental condition such as the failure of heat transfer tube of sodium-molten salt heat exchanger. Thus, this study is intended to investigate the reaction behavior of sodium-nitrate molten salt, which is one of the important phenomena in terms of safety assessment of the cited system. For the first step to clarify reaction behavior of sodium-nitrate molten salt, the thermal analyses using solar salt (NaNO
-KNO) were performed. It was confirmed that phase change behavior of solar salt is comparable to the thermochemical data base in case of reheated NaNO-KNO misture. Besides, the tests for sodium-solar salt reactions were carried out. It was found that sodium-solar salt reaction occurred after the solar salt melting.
Otaka, Toshiki*; Sato, Tatsumi*; Nakatani, Kiyoharu*; Nagoshi, Kohei*; Abe, Ryoji*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Kiriyama, Hiromitsu; Mori, Michiaki; Shimomura, Takuya; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Daito, Izuru; Suzuki, Masayuki*; Okada, Hajime; Ochi, Yoshihiro; et al.
no journal, ,
We describe two specific high intensity laser systems that are being developed in our laboratory for many applications such as high field science, nonlinear optics. We report on an ultra-high intensity petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 18 J with 30 fs pulse duration for studying extremely high intensity laser matter interaction process and a small-scaled Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 m J of 500 fs pulse duration for compact, high efficiency, high repetition system. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.
Kiriyama, Hiromitsu; Mori, Michiaki; Shimomura, Takuya; Nakai, Yoshiki*; Tanoue, Manabu*; Sasao, Hajime*; Kondo, Shuji; Kanazawa, Shuhei; Ochi, Yoshihiro; Tanaka, Momoko; et al.
no journal, ,
We report on a femtosecond high-intensity OPCPA/Ti:sapphire hybrid laser system that produces more than 30 J broadband output energy, indicating the potential for achieving petawatt-class peak powers. High temporal-contrast of 10
to 10
has been obtained with a near-perfect flat-topped spatial-profile of filling factor 80%. We also present a compact, high-intensity OPCPA/Yb:YAG hybrid laser system that generates 100 mJ output energy with a temporal contrast of better than 10 and good spatial beam quality.
Yomogida, Takumi; Yamada, Shinya*; Ichinohe, Yuto*; Sato, Toshiki*; Hayakawa, Ryota*; Okada, Shinji*; Toyama, Yuichi*; Hashimoto, Tadashi; Noda, Hirofumi*; Isobe, Tadaaki*; et al.
no journal, ,
The reduction of uranium on biotite was studied to obtain insight into the immobilization of uranium in the environment. The chemical species of uranium in biotite were studied using a superconducting transition edge sensor and an X-ray emission spectrometer to remove interference from rubidium in biotite. As a result, the speciation of uranium in biotite collected from former uranium deposits was possible. The XANES spectra of the biotite indicated that the uranium in the biotite was partially reduced.
Kikuchi, Shin; Sato, Rika; Kondo, Toshiki; Umeda, Ryota; Yamano, Hidemasa
no journal, ,
As part of the development of safety design technologies for sodium-cooled fast reactor coupled to thermal energy storage system with sodium-molten salt heat exchanger, we are considering the chemical reactivity between liquid metallic sodium and nitric acid-based molten salt, assuming boundary failure in heat exchangers. In this report, we present the preparation status of fundamental experiment and some results of preliminary experiment.
Sato, Rika; Kondo, Toshiki; Umeda, Ryota; Kikuchi, Shin; Yamano, Hidemasa
no journal, ,
In a sodium-cooled fast reactor (SFR) coupled to thermal energy storage system, the reaction between nitrate molten salt as thermal storage material and sodium (Na) as coolant of SFR may occur under the postulated accidental condition such as the failure of heat transfer tube of Na-molten salt heat exchanger. Thus, the reaction behavior of Na-nitrate molten salt is one of the important phenomena in terms of safety assessment of the cited system. In this study, the reaction experiment on Na-solar salt was performed to discuss the obtained results. It is found that Na-solar salt reaction occurred after the solar salt melting induced by eutectic melting of NaNO-KNO.
Nishimura, Akihiko; Asai, Toshiki; Kurosaka, Keiko; Sato, Masaomi; Hoshiya, Taiji
no journal, ,
Science Outreach Activities on Summer Science Camp has reported. This camp helps the promotion of science education around KANSAI. The camp has both seminars and experiments, which was widely announced by JST home-page since 2007.
