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Kinoshita, Norikazu*; Nagaoka, Mika; Nakanishi, Takashi*
Science of the Total Environment, 753, p.142087_1 - 142087_10, 2021/01
Times Cited Count：4 Percentile：26.95(Environmental Sciences)The distribution of the anthropogenic radionuclide americium-241 (
Am), a decay product of Pu discharged from atmospheric tests of nuclear weapons, was investigated to resolve its horizontal and vertical migration in the Tropical East Pacific. We analyzed Am concentrations in seawater samples collected in 2003. On comparing the Am concentrations with the previously determined concentrations of 
Pu in the same samples, the vertical profiles of Am were found to be similar to those of Pu. At some stations, the maximum concentration of Am occurred 100-200 m deeper than that of Pu. The Am/Pu ratios in the North Pacific and South Pacific were comparable to one another, and were typical of the ratio for the Pacific. The Am distribution was influenced by the water mass at depths below 400 m. The Am data support the view there is a current flowing at depths of 400-3000 m from the North Pacific through the equator to the South Pacific. In addition, the Am vertical profile was explained by using a box model that considers the decay of Pu and adsorption and scavenging by suspended particles. The different depths for the maximum concentrations of Am and Pu observed at some stations were well explained by the model and by the distribution of CaCO
particles. The residence time of Am in the Pacific was also estimated by using the model.
Ebihara, Kenichi
JAERI-Research 2005-004, 121 Pages, 2005/03
JAERI-Research-2005-004.pdf:19.79MB
This report is the JAERI's report version of the doctor thesis by the author. In this report, first, the validity and usefulness of the application of the two-phase fluid model of the lattice-gas method and the lattice Boltzmann method(LBM) are examined. On the basis of the examination, next, the horizontal stratified two-phase flow that is the fundamental and important flow is simulated by the HCZ model which is one of the two-phase fluid model of the LBM. It is seen that the interfacial growth of the HCZ model satisfies the Kelvin-Helmholtz instability theory and reproduces the theoretical two-phase flow regime map of Taitel and Dukler(T-D map). It is found that more superficial flow velocity of the rare phase is necessary in the channel with the narrow width. The HCZ model can also simulate the droplet generation accompanying more complex interfacial phenomena and reproduce the experimental correlation of Ishii and Grolmes in the range of the distribution of the experimental data.
Takeda, Nobukazu; Nakahira, Masataka; Kakudate, Satoshi; Takahashi, Hiroyuki*; Shibanuma, Kiyoshi; Yabana, Shuichi*; Matsuda, Akihiro*
Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.299 - 306, 2005/00
For the ITER, a fusion experimental reactor, it is planned to use rubber bearings in order to enhance the reliability of integrity with a sufficient margin even for the earthquakes beyond the design basis earthquake. In application for nuclear plants, the vertical compression of the isolator is 2
5 MPa and there is no experience for such a high compression as 10 MPa to be used for the ITER. Therefore, there is not enough design data of the rubber bearings with high compression, and thus a detailed estimation of performance is necessary. As a result of the endurance test after aging, it was validated that the bearing can be applied safely until 400th cycle even after 40 years of aging. On the other hand, the residual deformation was found at the 246th cycle. This means that the residual deformation can be observed enough earlier than the change of the macroscopic mechanical parameter such as stiffness. Therefore, it is possible to prevent break of the bearing during operation by sensing a sign of break with a periodical visual inspection.
Ebihara, Kenichi
Tsukuba Daigaku Daigakuin Shisutemu Joho Kogaku Kenkyuka Hakase Gakui Rombun, 134 Pages, 2004/09
In this thesis, first the liquid-gas models of the lattice method are examined by applying them to two-phase flow simulations. Next the liquid-gas model(the HCZ model) of the lattice Boltzmann method is applied to the three-dimensional simulation of the horizontal stratified two-phase flow. The following results are obtained. (1)The two- and three- dimensional interface simulated by the HCZ model satisfies the Kelvin-Helmholtz instability theory. (2)In the simulation of the interfacial growth in the rectangular channel, it is found that the relation between the interfacial growth and the flow state is in agreement with the flow regime map proposed theoretically by Taitel and Dukler. (3)It is also found that the three dimensionality becomes remarkable and the interfacial growth needs more flow rate of the rare phase than that of the theoretical flow regime map when the channel width is narrower. (4)In the droplet creation simulation, it is found that the relation between the droplet creation and the flow state simulates the experimental correlation proposed by Ishii and Grolmes.
Ebihara, Kenichi; Watanabe, Tadashi
Nagare, 23(4), p.253 - 261, 2004/08
The lattice Boltzmann method for one-component two-phase fluid is applied to the simulation of the droplet creation in the horizontal stratified two-phase flow. It is observed in several flow states that the droplet tears from the interface wave. The dimensionless numbers that characterize the flow state are also measured during the simulations. After checking the influence of the lattice length and width to the simulation result, the relation between the droplet creation and the measured dimensionless numbers is compared with the inception criteria of the droplet creation that was proposed on the basis of experimental data by Ishii and Grolmes. It was found that the simulation results are included in the devitation of experimental data from the correlation of Ishii-Grolmes.
Ebihara, Kenichi; Watanabe, Tadashi
Nihon Kikai Gakkai Rombunshu, B, 70(694), p.1393 - 1399, 2004/06
The horizontal stratified two-phase flow in the rectangular pipe whose width in smaller than the height is simulated by the one-component two-phase lattice Boltzmann method. The interfacial growth between two phases is measured for three cases with the different pipe width and the measured dimensionless number charactering the two-phase flow is compared with the flow regime map proposed by Taitel and Dukler. It is found that the boundary separating the interfacical growth from the non-growth which is obtained by the simulations is larger in the flow regime map when the pipe width is narrower.
Kondo, Masaya; Nakamura, Hideo; Anoda, Yoshinari; Saishu, Sadanori*; Obata, Hiroyuki*; Shimada, Rumi*; Kawamura, Shinichi*
Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 9 Pages, 2002/00
no abstracts in English
Arai, Kenji*; Kurita, Tomohisa*; Nakamaru, Mikihide*; Fujiki, Yasunobu*; Nakamura, Hideo; Kondo, Masaya; Obata, Hiroyuki*; Shimada, Rumi*; Yamaguchi, Ken*
Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 7 Pages, 2002/00
no abstracts in English
Nakamura, Hideo; Anoda, Yoshinari; Tabata, Hiroaki*; Obata, Hiroyuki*; Arai, Kenji*; Kurita, Tomohisa*
JAERI-Conf 2000-015, p.177 - 184, 2000/11
no abstracts in English
Nakamura, Hideo; Kondo, Masaya; Asaka, Hideaki; Anoda, Yoshinari; Tabata, Hiroaki*; Obata, Hiroyuki*
Proceedings of 2nd Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-2), p.336 - 343, 2000/00
no abstracts in English
Nakamura, Hideo; Kondo, Masaya; Kukita, Yutaka*
NUREG/CP-0160, p.661 - 675, 1998/09
no abstracts in English
Kubo, Shinji; Akino, Norio; *; *
Nihon Kikai Gakkai Rombunshu, B, 64(625), p.3013 - 3020, 1998/09
no abstracts in English
Kubo, Shinji; Akino, Norio; *; *; *
Nihon Kikai Gakkai Rombunshu, B, 64(623), p.336 - 344, 1998/07
no abstracts in English
Nakamura, Hideo; ; Kukita, Yutaka*
Nucl. Eng. Des., 184(2-3), p.339 - 348, 1998/00
Times Cited Count：7 Percentile：53.73(Nuclear Science & Technology)no abstracts in English
Nakamura, Hideo; ; *; Tsuji, Yoshiyuki*; Kukita, Yutaka*
Bulletin of the Research Laboratory for Nuclear Reactors, (SPECIAL ISSUE 2), p.35 - 46, 1997/00
no abstracts in English
*; *; Kubo, Shinji; Akino, Norio; *; Takase, Kazuyuki
Kashika Joho Gakkai-Shi, 18(68), p.1 - 8, 1997/00
no abstracts in English
*; Tsuji, Yoshiyuki*; *; Nakamura, Hideo; ; Kukita, Yutaka
Nihon Genshiryoku Gakkai-Shi, 39(8), p.669 - 680, 1997/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
; Kukita, Yutaka
Journal of Nuclear Science and Technology, 33(9), p.696 - 702, 1996/09
Times Cited Count：2 Percentile：24.71(Nuclear Science & Technology)no abstracts in English
*; Kunugi, Tomoaki; *
Album of Visualization,No. 13, 0, p.19 - 20, 1996/00
no abstracts in English
Maruyama, Yu; Igarashi, Minoru*; Hashimoto, Kazuichiro; Nakamura, Naohiko*; Hidaka, Akihide; Sugimoto, Jun
Transactions of the American Nuclear Society, 75, p.273 - 274, 1996/00
no abstracts in English
