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Yamanoi, Kazuto*; Sakakibara, Yuri*; Fujimoto, Junji*; Matsuo, Mamoru; Nozaki, Yukio*
Applied Physics Express, 16(6), p.063004_1 - 063004_6, 2023/06
Times Cited Count：0 Percentile：0(Physics, Applied)Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
JAEA-Technology 2020-020, 73 Pages, 2021/03
JAEA-Technology-2020-020.pdf:8.26MB
The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.
Onuki, Yoshichika*; Kakihana, Masashi*; Iha, Wataru*; Nakaima, Kenri*; Aoki, Dai*; Nakamura, Ai*; Honda, Fuminori*; Nakashima, Miho*; Amako, Yasushi*; Gochi, Jun*; et al.
JPS Conference Proceedings (Internet), 29, p.012001_1 - 012001_9, 2020/02
Sato, Junya; Kikuchi, Hiroshi*; Kato, Jun; Sakakibara, Tetsuro; Matsushima, Ryotatsu; Sato, Fuminori; Kojima, Junji; Nakazawa, Osamu
QST-M-8; QST Takasaki Annual Report 2016, P. 62, 2018/03
no abstracts in English
Kato, Jun; Nakagawa, Akinori; Taniguchi, Takumi; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro
JAEA-Review 2017-015, 173 Pages, 2017/07
JAEA-Review-2017-015.pdf:6.67MB
Various radioactive wastes have been generated at the Fukushima Daiichi Nuclear Power Station (1F). To dispose of the wastes underground, it is necessary to make a suitable waste package by the volume reduction and solidification of the wastes. To plan the future decommissioning of 1F, it is also necessary to estimate feasibility of existing treatment technology for those wastes. Therefore the document survey has been performed about volume reduction and solidification technologies that have domestic or foreign experiences of practical treatment for radioactive wastes to assist selection of suitable treatment of the wastes. This report shows the arranged results. The 1F wastes are classified into two groups, homogeneous particulate and liquid wastes and heterogeneous solid wastes. The needful items for the feasibility study such as a technology name, a fundamental principle, treatment efficiency, and characteristic of solidified waste are summarized in each group.
Sato, Junya; Suzuki, Shinji*; Kato, Jun; Sakakibara, Tetsuro; Meguro, Yoshihiro; Nakazawa, Osamu
QST-M-2; QST Takasaki Annual Report 2015, P. 87, 2017/03
no abstracts in English
Sato, Junya; Suzuki, Shinji*; Kato, Jun; Sakakibara, Tetsuro; Meguro, Yoshihiro; Nakazawa, Osamu
QST-M-2; QST Takasaki Annual Report 2015, P. 88, 2017/03
no abstracts in English
Kubota, Kenji*; Kondo, Keiji; Sakakibara, Junichi*
Shadan Hojin Butsuri Tansa Gakkai Dai-128-Kai (Heisei-25-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.62 - 65, 2013/06
To evaluate the excavated damaged zone (EDZ) is one of the important factors to conduct high level radioactive waste disposal. We have conducted resistivity and acoustic tomography to evaluate EDZ during the excavation of the test tunnel at a depth of 140 m and 250 m. As a result, a few meters extent of high resistivity and low P-wave velocity zone were detected at a depth of 140 m. This suggests that EDZ by excavation of horizontal tunnel was estimated by resistivity and acoustic tomography. On the other hand, high resistivity zone were not detected at a depth of 250 m.
Yamaguchi, Akira*; Tatsumi, Eisaku*; Takata, Takashi*; Ito, Kei; Ohshima, Hiroyuki; Kamide, Hideki; Sakakibara, Jun*
Nuclear Engineering and Design, 241(5), p.1627 - 1635, 2011/05
Times Cited Count：6 Percentile：44.28(Nuclear Science & Technology)In a sodium-cooled fast reactor, inert gases exist in the primary coolant system either in a state of dissolved gas or free gas bubbles. In the present study, a gas entrainment allowance level at the free surface is discussed and rationalized. The influence of the gas entrainment is evaluated using the void fraction at the core inlet. For the purpose, a plant dynamics code VIBUL has been developed to evaluate the concentration distribution of the dissolved gas and the free gas bubble. It is noted that the background level is already very low in comparison with the induced void reactivity by the void passing the reactor core.
Yamaguchi, Akira*; Takata, Takashi*; Tatsumi, Eisaku*; Ito, Kei; Ohshima, Hiroyuki; Kamide, Hideki; Sakakibara, Jun*
Proceedings of 7th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-7) (CD-ROM), 16 Pages, 2008/10
In a sodium-cooled fast reactor, inert gases exist in the primary coolant system either in a state of dissolved gas or free gas bubbles. The gas in the primary system may cause disturbance in reactivity, nucleation site for boiling, etc. Therefore, the allowance level is necessary regarding the gas entrainment and the gas bubble concentration. In the present study, a gas entrainment allowance level is discussed and rationalized. For the purpose, a plant dynamics code VIBUL has been developed to evaluate the concentration distribution of the dissolved gas and the free gas bubble. Assuming that the total void fraction should be kept below 105% of the background level, a preliminary design allowance level of gas entrainment is proposed as the map in terms of the entrainment ratio and the entrained bubble radius. Furthermore, the possibility of bubble removal is investigated to satisfy the allowance level.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Nuclear Fusion, 47(10), p.S668 - S676, 2007/10
Times Cited Count：34 Percentile：73.71(Physics, Fluids & Plasmas)The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5
10
m
, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.
Yagyu, Junichi; Sasajima, Tadayuki; Miyo, Yasuhiko; Sakakibara, Satoru*; Kawamata, Yoichi
JAEA-Technology 2007-015, 27 Pages, 2007/03
JAEA-Technology-2007-015.pdf:2.94MB
The feedback control of the plasma position and shape based on signals of magnetic probes is performed on JT-60. The fabrication cost of these magnetic probes is very high. Therefore, the cost reduction is required for the use in a next device. On the other hand, the magnetic field measurement in three axial directions with the advanced technology (AT) probes is simultaneously made on LHD of NIFS. The AT-probe has been developed at a low fabrication cost and in compact size and light weight. The possibility of application of the AT-probe in a Tokamak device (JT-60U) has been investigated in collaboration between JAEA and NIFS. We designed and fabricated the casing and interface for the AT-probe, and installed it under the first wall of JT-60U. A comparison of output signals between the installed AT-probe and a existing magnetic probe was made. Tests have been carried out to evaluate the vibration resistance and the radioactive resistance through about two thousand shots with high performance plasmas including one hundred disruption shots in JT-60U. As a result, the AT-probe has a good performance and an enough usable prospect in environment of the Tokamak device.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03
The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high 
and long pulse.
Sasajima, Tadayuki; Yagyu, Junichi; Miyo, Yasuhiko; Miya, Naoyuki; Sakakibara, Satoru*
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Kumada, Takayuki; Sakakibara, Masahiro*; Nagasaka, Toshimitsu*; Fukuta, Hiroya*; Kumagai, Jun*; Miyazaki, Tetsuo*
Journal of Chemical Physics, 116(3), p.1109 - 1119, 2002/01
Times Cited Count：44 Percentile：77.99(Chemistry, Physical)We have studied diffusion and recombination of H atoms in solid hydrogen using ESR, ENDOR, and ESE spectrometer. The rate constant for recombination of H atoms in highly purified parahydrogen was found to be much smaller than that expected by diffusion coefficient. This result indicates that the H atoms do not recombine in the absence of energy dispersion path in highly purified parahydrogen.
Esaka, Fumitaka; Magara, Masaaki; Hanzawa, Yukiko; Sakurai, Satoshi; Taguchi, Takuji; Takai, Konomi; Sakakibara, Takaaki; Kurosawa, Setsumi; Takahashi, Masato; Yasuda, Kenichiro; et al.
Dai-22-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, 8 Pages, 2001/11
no abstracts in English
Matsui, Goichi*; Monji, Hideaki*; Sakakibara, Jun*; Tanaka, Masaaki; Kobayashi, Jun; Kamide, Hideki
PNC TY9610 98-001, 58 Pages, 1998/03
None
Takamine, Jun; Haruyama, Mitsuo; Takase, Misao; Yamaguchi, Satoshi; Yamaguchi, Hiromi; Sakakibara, Tetsuro; Akashi, Kenichi*
no journal, ,
no abstracts in English
Kubota, Kenji*; Suzuki, Koichi*; Sugita, Yutaka; Sakakibara, Junichi*
no journal, ,
no abstracts in English
Hanari, Toshihide; Sugihara, Kenta; Muramatsu, Toshiharu; Yamashita, Masanori*; Sakakibara, Jun*
no journal, ,
no abstracts in English
