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Yasuda, Satoshi; Tamura, Kazuhisa; Terasawa, Tomoo; Yano, Masahiro; Nakajima, Hideaki*; Morimoto, Takahiro*; Okazaki, Toshiya*; Agari, Ryushi*; Takahashi, Yasufumi*; Kato, Masaru*; et al.
Journal of Physical Chemistry C, 124(9), p.5300 - 5307, 2020/03
Times Cited Count：14 Percentile：59.2(Chemistry, Physical)Confinement of hydrogen molecules at graphene-substrate interface has presented significant importance from the viewpoints of development of fundamental understanding of two-dimensional material interface and energy storage system. In this study, we investigate H
confinement at a graphene-Au interface by combining selective proton permeability of graphene and the electrochemical hydrogen evolution reaction (electrochemical HER) method. After HER on a graphene/Au electrode in protonic acidic solution, scanning tunneling microscopy finds that H nanobubble structures can be produced between graphene and the Au surface. Strain analysis by Raman spectroscopy also shows that atomic size roughness on the graphene/Au surface originating from the HER-induced strain relaxation of graphene plays significant role in formation of the nucleation site and H storage capacity.
Wada, Yuki*; Bowers, G. S.*; Enoto, Teruaki*; Kamogawa, Masashi*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Smith, D.*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; et al.
Geophysical Research Letters, 45(11), p.5700 - 5707, 2018/06
Times Cited Count：30 Percentile：81.28(Geosciences, Multidisciplinary)Shibama, Yusuke; Okano, Fuminori; Yagyu, Junichi; Kaminaga, Atsushi; Miyo, Yasuhiko; Hayakawa, Atsuro*; Sagawa, Keiich*; Mochida, Tsutomu*; Morimoto, Tamotsu*; Hamada, Takashi*; et al.
Fusion Engineering and Design, 98-99, p.1614 - 1619, 2015/10
Times Cited Count：4 Percentile：32.95(Nuclear Science & Technology)The JT-60SA vacuum vessel (150 tons) is a double wall torus structure and the maximum major radius of 5.0 m and height of 6.6 m. The manufacturing design concept is that the vessel is split in the 10 toroidal sectors manufactured at factory, and assembled on-site; seven of the 40-degree sectors, two of the 30-degree beside final one, and the final of the 20-degree. The final sector is assembled with the VV thermal shield and toroidal field magnets into the 340-degree as prepared in one sector. Sectors are temporally fitted on-site and adjusted one over the other before the assembly. After measurement of the dimensions and the reference, these sectors are transferred onto the cryostat base. First, three 80-degree sectors are manufactured with mating each 40-degree sector by direct joint welding. The rest sectors including the final sector are jointed with splice plates. Welding manipulator and its guide rails are used for these welding. In this paper, the detail of the VV sectors assembly including the final sector is explained. Welding technologies to joint the two of 40-degree sectors are reported with the present manufacturing status and the welding trial on the vertical stub with the partial mock-up of the final sector are discussed with the assembly process.
*; Kawashima, Masatoshi*
PNC TJ9164 96-017, 142 Pages, 1996/03
Accurate prediction methods for reactivity feedback coefficients such as power reactivity coefficients are most important to the core transiat test planning for safety capability demonstration using JOYO plant. This analysis studied components of feactivity feedback coefficients in the MK-III core, taking into accounts for fuel irradiation histories. The principal results are summarized as follows. Larger effects are expected to the reactivity feedback coefficients associated with fuel expansion and the Doppler components in the MK-III core than those in the MK-II cores, beause the MK-III core has the enlarged zones for high linear heat rating by by lateral zoning. This fact requires that fuel pin irradiation histories should be considered to the power coefficient prediction in the MK-III cores. The proposed model is appliable for the MK-III core reflecting experiences obtained in the MK-II core analyses, because the profiles and the component fractions of power reactivity coefficients in the MK-III cores are almost similar to those in the MK-II cores.
Kawashima, Masatoshi*; *
PNC TJ9164 96-012, 153 Pages, 1996/03
"MAGI" system renewal aims at improving the prediction accuracy for the neutronic and thermal characteristics along with the plant upgrade. Present work discussed the grand design of the system and prepared neutron flux distribution calculation module. The grand design study has determined that the system would cover pre-operation prediction function and post-operation recording function. It was proposed that the prediction calculations would enhance safety confirmation for power distributions and other major nuclear and thermal hydraulic chracteristics because the MK-III core would achieve power uprating with two-zoned regions. A prototypic flux calculation module was made with finite-difference 3-dimentional diffusion formulation for the Tri-Z geometry. The basic methodology for the new system includes 24mesh points per hexagon and 18 energy groups. The module was applied to the MK-III core as sample calculations. To proceed the "MAGI" system renewal, it is required to establish items to be compared with safety criteria using the neutronic module outputs. In addition, it needs to make the basic modules of the system for calculation control, constant preparation, various characteristics calculation, and IO control modules.
Akino, Norio; *; *; Kubo, Shinji; *; *
Dai-32-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu, 0, p.307 - 308, 1995/05
no abstracts in English
Kawashima, Masatoshi*; *
PNC TJ9164 96-003, 149 Pages, 1995/03
The core management code system "MAGI" was developed for the Experimental Fast Reactor, JOYO. The "MAGI" system upgrade aims at improving the prediction accuracy for the neutronic and thermal characteristics along with the plant up-grade. To achieve the goals, new appropriate methodology is needed for local characteristic predictions in the core and surrounging regions. The new basic methodology includes fine mesh-spacing (24 mesh poins per hexagon) and increased energy groups (18 neutron and 7 ga㎜a groups) with diffusion calculation. To utilize the fine mesh-spacing model with improved heterogeneous structures for varaious types of subassembly, simple rules are proposed for modeling, based on the numerical comparisons for reactivity worth, power distributions and burnup composition variations. To realize the "MAGI" system upgrade, it is required to establish further detail rules for various irradiation rigs for data flow specifications. It is also required to make the basic modules of the system, hereafter.
*; Kawashima, Masatoshi*
PNC TJ9164 96-002, 207 Pages, 1995/03
As for demonstrating inherent safety features in fast reactors, transient safety tests will be planned using the experimental fast reactor JOYO. Accurate prediction for power reactivity-coefficients is most important to the core transients prediction. This work analysed the power coefficients measured in the initial and 27th cycles for the MK-2 cores. Major emphases were placed on the fuel temperature calculations and fuel axial expansion modelling proposed. The analyses explained that the observed systematic variations with core burnup were reproduced fairly well combining with two aspects mentioned above. These results have implied that further studies would incude adjustment methodology developement for the proper basic feedback model through various measurements as to establishing total reactivity feedback model to the Joyo core. Such methodology development efforts are required to the core bowing reactivity effects and feedback factors assosiated with the plant structure and oprational schemes, hereafter.
Akino, Norio; Kubo, Shinji; *; *; *; *
Dai-31-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu, 0, p.370 - 372, 1994/00
no abstracts in English
Morimoto, Makoto; Okubo, Toshiyuki; ; ; ; ;
PNC TN9410 91-334, 64 Pages, 1991/10
An failed fuel detection and location system (FFDL) using a sipping method is adopted as the FFDL of Joyo. FFDL has not operated since the first falled fuel simulated (FFDL-I) test in April, 1985 because Joyo has not yet experienced any operation with breached fuels. Therefore, the operational test (II) of FFDL was carried out on July 12
19, 1991 for a preparation of the FFDL-II test which is scheduled in 1992. Main results from the test are as follows ; (1)The adequacy of the functions and operating procedure of FFDL was reaffirmed and the operating experience was gained. (2)Radioactivity measurement was conducted by FFDL for six subassemblies and their integrity was confirmed.
*; Morimoto, Makoto*; *; *; *; Kuroha, Mitsuo; *
PNC TN941 77-104, 101 Pages, 1977/06
After finishing first phase test, the 1MW Steam Generator was modified and second phase test was started from February 1973 and finished the test by June 1975. Then the steam Generator was dismantled, cleaned, and structural materials of the steam generator were externally inspected. This is to report the progress of operation of second phase test, repairing of facility and to describe the details of dismantling and cleaning of the steam generator addng the explanations of external inspection with photographs. Items clarified by the second phase test, followed by dismantling and cleaning were as follows : (1)Modifications based on the first phase test results were effective to improve the performance of the steam generator. (2)It was demonstrated that the cleaning of steam generator by flushing mixture of steam and argon gases was safe and effective. (3)During the external inspection after dismantling, they were observed slight deformations, and in way of the tube supports, wearing of tubes, which was supposed to be caused by fretting, was also observed.
Shibama, Yusuke; Okano, Fuminori; Yagyu, Junichi; Kaminaga, Atsushi; Miyo, Yasuhiko; Hayakawa, Atsuro*; Sagawa, Keiich*; Mochida, Tsutomu*; Morimoto, Tamotsu*; Hamada, Takashi*; et al.
no journal, ,
no abstracts in English
Es region by Coulomb excitation 
-ray spectroscopyYanagihara, Rikuto; Ideguchi, Eiji*; Nishio, Katsuhisa; Orlandi, R.; Makii, Hiroyuki; Asai, Masato; Hirose, Kentaro; Tsukada, Kazuaki; Toyoshima, Atsushi; Sato, Tetsuya; et al.
no journal, ,
Md produced in the 
He+Es reactionNishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; Kean, K. R.*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi*; Sato, Tetsuya; Ito, Yuta; et al.
no journal, ,
no abstracts in English
Hirose, Kentaro; Nishio, Katsuhisa; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Nagame, Yuichiro*; et al.
no journal, ,
A specific phenomenon was found in fission-fragment mass distributions for nuclides around A=258 by spontaneous fission measurements. Fm256 splits into light and heavy fragments, like uranium isotopes, making two peaks in their mass distribution, whereas a sharp single peak was found in that of Fm258 which has only two more neutrons. In order to study such a specific phenomenon more widely, we performed an experiment of the multinucleon transfer fission in the O18+Es254 reaction at JAEA Tokai tandem accelerator facility.
Md produced in the He + Es reactionNishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; Kean, K. R.*; Tsukada, Kazuaki; Toyoshima, Atsushi*; Asai, Masato; Sato, Tetsuya; Chiera, N. M.*; et al.
no journal, ,
no abstracts in English
Md produced in the He + Es reactionNishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; Kean, K. R.*; Tsukada, Kazuaki; Toyoshima, Atsushi*; Asai, Masato; Sato, Tetsuya; Chiera, N. M.*; et al.
no journal, ,
no abstracts in English
