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Uesawa, Shinichiro; Ono, Ayako; Nagatake, Taku; Yamashita, Susumu; Yoshida, Hiroyuki
Journal of Nuclear Science and Technology, 62(5), p.432 - 456, 2025/05
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)We performed electrostatic simulations of a wire-mesh sensor (WMS) for a single spherical bubble and bubbly flow to clarify the accuracy of the WMS. The electrostatic simulation for the single bubble showed the electric current density distribution and the electric current path from the excited transmitter to receivers for various bubble locations. It indicated systematic errors based on the nonuniform current density distribution around the WMS. The electrostatic simulation for the bubbly flow calculated by the computational fluid dynamics code, JAEA Utility Program for Interdisciplinary Thermal-hydraulics Engineering and Research (JUPITER), indicated that the WMS had difficulty in quantitatively measuring the intermediate values of the instantaneous void fraction between 0 and 1 because they cannot be estimated by previous transformation methods from the WMS signal to the void fraction, such as linear approximation or Maxwell's equation, and have a significant deviation of the void fraction of 
0.2 for the WMS signal. However, the electrostatic simulation indicated that the time-averaged void fractions around the center of the flow channel can be estimated using linear approximation, and the time-averaged void fraction near the wall of the flow channel can be estimated using Maxwell's equation.
C alloy measured in the electrostatic levitation furnace onboard the international space stationIshikawa, Takehiko*; Oda, Hirohisa*; Koyama, Chihiro*; Shimonishi, Rina*; Ikeuchi, Rumiko*; Paradis, P.-F.*; Okada, Jumpei*; Fukuyama, Hiroyuki*; Yamano, Hidemasa
International Journal of Microgravity Science and Application, 42(2), p.420202_1 - 420202_10, 2025/04
Uesawa, Shinichiro; Ono, Ayako; Yamashita, Susumu; Yoshida, Hiroyuki
Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 7 Pages, 2024/11
A conductance-typed wire-mesh sensor (WMS), utilizing the difference in conductivity between gas and liquid phases between the electrodes, is one of the practical measurement techniques of a cross-sectional void fraction distribution in a flow path. In this study, we performed two-phase computational fluid dynamics (CFD) and electrostatic simulations around a WMS for a single spherical bubble and bubbly flow to clarify the systematic error in the WMS. The results for the single bubble indicated that there were systematic errors based on the non-uniform current density distribution around the WMS. The correlation between instantaneous void fractions and WMS signals is not uniquely determined for positions of the single bubble moving across the WMS, even for the same bubble. Moreover, the correlation between the instantaneous void fractions and the WMS signals did not fit in a linear approximation and Maxwell's equation, which traditionally used transformation methods from the WMS signal to the void fraction. The results for the bubbly flow indicated that the WMS had difficulty in quantitative measurements of the instantaneous void fraction because the values had a significant deviation of the void fraction of approximately 0.2. On the other hand, time-averaged void fraction values had relatively small deviation. Thus, we concluded that the WMS, using existing transformation methods, can measure time-averaged void fractions, but it is difficult to measure quantitatively instantaneous void fractions.
Yoshida, Go*; Matsumura, Hiroshi*; Nakamura, Hajime*; Miura, Taichi*; Toyoda, Akihiro*; Masumoto, Kazuyoshi*; Nakabayashi, Takayuki*; Matsuda, Makoto
Journal of Nuclear Science and Technology, 61(10), p.1298 - 1307, 2024/10
Times Cited Count：1 Percentile：0.00(Nuclear Science & Technology)Collaborative Laboratories for Advanced Decommissioning Science; Ibaraki University*
JAEA-Review 2023-021, 112 Pages, 2024/02
JAEA-Review-2023-021.pdf:7.1MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Contribution to Risk Reduction in Decommissioning Works by the Elucidation of Basic Property of Radioactive Microparticles" conducted from FY2018 to FY2021 (this contract was extended to FY2021). The present study aims to understand the basic properties (size, chemical composition, isotopic composition - including concentration of 
-emitters, electrostatic properties, and optical properties, etc.) of fine particles composed of silicate with insoluble properties which contain regions of highly concentrated radioactive cesium (Cs) released to the environment by the accident at the Fukushima Daiichi Nuclear Power Station of TEPCO in 2011 March.
Kitamura, Akira; Yoshida, Yasushi*
Journal of Radioanalytical and Nuclear Chemistry, 327(2), p.839 - 845, 2021/02
Times Cited Count：5 Percentile：39.12(Chemistry, Analytical)Thermodynamic data for radium for radioactive waste management have been predicted using an electrostatic model and correlation with the ionic radii of the alkaline earth metals. Estimation of the standard Gibbs free energy of formation and standard molar entropy of aqueous radium species and compounds has been based on such approaches as extrapolation of the thermodynamic properties of strontium and barium, and use of a model of ion pair formation. The predicted thermodynamic data for radium have been compared with previously reported values.
Collaborative Laboratories for Advanced Decommissioning Science; Ibaraki University*
JAEA-Review 2020-033, 84 Pages, 2021/01
JAEA-Review-2020-033.pdf:4.9MB
JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2018, this report summarizes the research results of the "Contribution to Risk Reduction in Decommissioning Works by the Elucidation of Basic Property of Radioactive Microparticles" conducted in FY2019.
Collaborative Laboratories for Advanced Decommissioning Science; Ibaraki University*
JAEA-Review 2019-041, 71 Pages, 2020/03
JAEA-Review-2019-041.pdf:3.38MB
JAEA/CLADS, has been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") since FY2018. The Project aims at solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence has been collected from all over the world, and basic research and human resource development have been promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Contribution to Risk Reduction in Decommissioning Works by the Elucidation of Basic Property of Radioactive Microparticles". In order to establish the decommissioning procedures (recovery of the melted fuels, decontamination inside the reactors, ensuring the safety of the workers, etc.) of the Fukushima Daiichi Nuclear Power Station, radioactive microparticles released by the accident are an important information source for clarifying what had happened inside the reactors in the course of the accident. The purpose of the present study is to obtain detailed knowledge on the basic properties (particle size, composition, electrical/optical properties, etc.) of the radioactive microparticles, as well as to further elucidate the various properties of the radioactive microparticles including the quantitative evaluation of alpha-ray-emitters, through the Japan-UK synergetic research. Thus, we are conducting research and development that will contribute to the comprehensive works towards the risk reduction in the "decommissioning" plan.
Mizuhashi, Kiyoshi; Uno, Sadanori; Okoshi, Kiyonori; Chiba, Atsuya; Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Sakai, Takuro; Sato, Takahiro; Yokota, Wataru; et al.
JAEA-Review 2005-001, TIARA Annual Report 2004, P. 371, 2006/01
no abstracts in English
Hachiue, Shunsuke; Teraoka, Yuden
JAERI-Tech 2004-066, 69 Pages, 2004/11
JAERI-Tech-2004-066.pdf:7.44MB
In order to progress chemical reaction studies at verious material surfaces using high speed and reactive ions and neutral particles beams, a high-speed neutral atomic and molecular beam apparatus has been developed. In this report, details of the apparatus and characteristics of actually-generated oxygen atomic and molecular ion/neutral beams are discribed. This apparatus is a ultra-high vacuum system consisting of a plasma ion source, electrostatic lens systems, a mass separator, and a charge transfer chamber. Total oxygen ion currents of 52 microamps at accerelation energy of 8 keV and 17 microamps even at 20 eV were obtained. Mass separation was also good so that an oxygen molecular ion beam of 11 microamps and an oxygen atomic ion beam of 5.5 microamps were obtained even at 20 eV. A neutral oxygen atomic or molecular beam was also generated with the flux density of 10
particles/cm
/s.
ion beams in a proof-of-principle accelerator for ITERInoue, Takashi; Taniguchi, Masaki; Dairaku, Masayuki; Hanada, Masaya; Kashiwagi, Mieko; Morishita, Takatoshi; Watanabe, Kazuhiro; Imai, Tsuyoshi
Review of Scientific Instruments, 75(5), p.1819 - 1821, 2004/05
Times Cited Count：11 Percentile：49.85(Instruments & Instrumentation)The paper reports progress of proof-of-principle test of negative ion accelerator for ITER. The accelerator structure is immersed in vacuum, surrounded by a FRP insulator column as the vacuum boundary. So far, the beam energy has been limited due to poor voltage holding capability of the FRP insulator column. By lowering the electric field strength at the triple junction (interface of FRP insulator, metal flange and vacuum) with large stress ring installed inside the insulator column, high voltage of 1 MV was stably sustained for more than 2 hours. In the following beam test, acceleration of 900 keV, 100 mA H ion beam was succeeded. Although the current was lower (70 mA) at 1 MeV, the beam of this level has been stably accelerated for 6 days, 130 shots in total (each pulse length: 1 s).
Pinak, M.
Computational Biology and Chemistry, 27(3), p.431 - 441, 2003/07
Times Cited Count：9 Percentile：44.13(Biology)One nanosecond molecular dynamics (MD) simulation was performed for two DNA segments each composed of 30 base pairs. The analysis of results was focused on the electrostatic energy that is supposed to be significant factor causing the disruption of DNA base stacking in DNA duplex and may also to serve as a signal toward the repair enzyme informing on the presence of the lesion. This electrostatic potential may signal presence of the lesion to the repair enzyme.
Yoshikawa, Kiyoshi*; Inoue, Nobuyuki*; Yamazaki, Tetsuo*; Makino, Keisuke*; Yamamoto, Yasushi*; Toku, Hisayuki*; Masuda, Kai*; Kii, Toshiteru*; Onishi, Masami*; Horiike, Hiroshi*; et al.
JAERI-Tech 2002-020, 63 Pages, 2002/03
JAERI-Tech-2002-020.pdf:4.94MB
no abstracts in English
Watanabe, Kazuhiro; Fujiwara, Yukio; Hanada, Masaya; Kashiwagi, Mieko; Kitagawa, Tadashi*; Miyamoto, Kenji; Morishita, Takatoshi; Okumura, Yoshikazu; Takayanagi, Tomohiro; Taniguchi, Masaki
Review of Scientific Instruments, 71(2), p.1231 - 1233, 2000/02
Times Cited Count：10 Percentile：54.23(Instruments & Instrumentation)no abstracts in English
Pinak, M.*
Journal of Molecular Structure; THEOCHEM, 466, p.219 - 234, 1999/00
no abstracts in English
Watanabe, Kazuhiro; Fujiwara, Yukio; Hanada, Masaya; Inoue, Takashi; Miyamoto, Kenji; Miyamoto, Naoki*; Ohara, Yoshihiro; Okumura, Yoshikazu
Review of Scientific Instruments, 69(2), p.986 - 988, 1998/02
Times Cited Count：3 Percentile：35.10(Instruments & Instrumentation)no abstracts in English
Matsuda, Makoto; Takeuchi, Suehiro; Kobayashi, Chiaki*
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.165 - 167, 1997/00
no abstracts in English
Okumura, Yoshikazu; Araki, Masanori; Hanada, Masaya; Inoue, Takashi; Kunieda, Shunsuke; Kuriyama, Masaaki; Matsuoka, Mamoru; Mizuno, Makoto; Ohara, Yoshihiro; Tanaka, Masanobu*; et al.
Production and Neutralization of Negative Ions and Beams; AIP Conference Proceedings 287, p.839 - 848, 1994/00
no abstracts in English
Kishimoto, Yasuaki; ; ; Odajima, Kazuo; Maeda, Hikosuke
JAERI-M 89-088, 27 Pages, 1989/07
no abstracts in English
and XeF ion beams for the tandem electrostatic accelerators; Abe, Shinichi; ; ; ; ; Hanashima, Susumu
Nuclear Instruments and Methods in Physics Research B, 5, p.217 - 220, 1984/00
Times Cited Count：5 Percentile：63.07(Instruments & Instrumentation)no abstracts in English
