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Sc
)
O
determined by single-crystal neutron diffractionTanaka, Seiya*; Kiyanagi, Ryoji; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Maruyama, Kenichi*; Utsumi, Shigenori*
Physical Review Materials (Internet), 7(1), p.014403_1 - 014403_11, 2023/01
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Sc)O (0 
x 0.2) hexagonal ferriteMaruyama, Kenichi*; Tanaka, Seiya*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Utsumi, Shigenori*; et al.
Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02
Times Cited Count：2 Percentile：15.51(Chemistry, Physical)Sc)O single crystalsUtsumi, Shigenori*; Tanaka, Seiya*; Maruyama, Kenichi*; Amako, Yasushi*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; 9 of others*
ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09
Times Cited Count：4 Percentile：20.20(Chemistry, Multidisciplinary)Fabricating large, high-crystalline-quality single-crystal samples of hexagonal ferrite Ba(FeSc)O is the first important step to elucidating its helimagnetic structure and developing it for further applications. In this study, single crystals of Ba(FeSc)O of various Sc concentrations 
were successfully grown by the spontaneous crystallization method using Na
O-FeO
flux. X-ray diffraction and elemental analysis revealed that the obtained crystals were composed of single-phase Ba(FeSc)O of high crystalline quality. The temperature dependence of magnetization and the magnetization curves at 77 K of the = 0.128 crystal exhibited behavior characteristics of helimagnetism. Neutron diffraction measurements of the = 0.128 crystal exhibited magnetic satellite reflection peaks below 211K, proving evidence that Ba(FeSc)O behaves as a helimagnetic material.
Noguchi, Yuto; Maruyama, Takahito; Ueno, Kenichi; Komai, Masafumi; Takeda, Nobukazu; Kakudate, Satoshi
Fusion Engineering and Design, 109-111(Part B), p.1291 - 1295, 2016/11
Times Cited Count：2 Percentile：19.46(Nuclear Science & Technology)This paper reports the impact hammer test of the full-scale mock-up of ITER Blanket Remote Handling system (BRHS). Since the BRHS, which is composed of the articulated rail and the vehicle manipulator which travels on the rail deployed in the vacuum vessel, is subjected to the floor response spectrum with 14 G peak at 8 Hz, evaluation of dynamic response of the system is of essential importance. Recently impact hammer testing on the full-scale mock-up of the BRHS was carried out to verify the finite element method seismic analysis and to experimentally obtain the damping ratio of the system. The results showed that the mock-up has a vertical major natural mode with a natural frequency of 7.5 Hz and a damping ratio of 0.5%. While higher structural damping ratios is predicted in a high amplitude excitation such as major earthquake, it was confirmed that the experimental natural major frequencies are in agreement with the major frequencies obtained by elastic dynamic analysis.
Saito, Makiko; Ueno, Kenichi; Maruyama, Takahito; Murakami, Shin; Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka*; Tesini, A.*
Fusion Engineering and Design, 89(9-10), p.2352 - 2356, 2014/10
Times Cited Count：8 Percentile：53.05(Nuclear Science & Technology)After plasma operation of the ITER reactor, irradiated radioactive dust will accumulate in the vacuum vessel (VV). The In Vessel Transporter (IVT) will be installed in the VV and remove the blanket modules for maintenance. The IVT will be carried back to the Hot Cell Facilities (HCF) after exchanging the blanket, and the IVT itself also needs maintenance. It is considered that the maintenance workers will be exposed to the irradiated radioactive dust attached to the IVT surface. In this study, dust contamination of the IVT is evaluated to assess exposure during maintenance work in the HCF. The IVT contamination scenario is assumed in the ITER project. From plasma shut down until maintenance is performed on the IVT will take 345 days under the ITER project assumption. Under this scenario, the effective dose rate from irradiated radioactive dust was calculated as an infinite plate for each nuclide. As a result, W-181 and Ta-182 were the dominant nuclides for the effective dose rate. If all dust is W-181 or Ta-182, the effective dose rate is about 400 
Sv/h and 100 Sv/h respectively. Nevertheless, using the dose limit determined by the ITER project and the estimated maximum maintenance time, the effective dose rate limit was calculated to be 4.18 Sv/h under these limited conditions. To satisfy the dose rate limit, decontamination processes were assumed and the dose rate after decontamination was evaluated.
Ueno, Kenichi; Aburadani, Atsushi; Saito, Makiko; Maruyama, Takahito; Takeda, Nobukazu; Murakami, Shin; Kakudate, Satoshi
Plasma and Fusion Research (Internet), 9, p.1405012_1 - 1405012_4, 2014/02
Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.
Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04
Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Takahashi, Nobuaki; Aizawa, Kazuya; Suzuya, Kentaro; Shibata, Kaoru; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB028_1 - SB028_6, 2011/05
Times Cited Count：125 Percentile：95.69(Physics, Multidisciplinary)AMATERAS is a cold-neutron disk-chopper spectrometer in MLF, J-PARC. The construction of main part of the spectrometer has been completed in spring of 2009. Soon after that, we have started the commissioning work on AMATERAS. The performance of AMATERAS has been examined by test experiments in the course of commissioning. In parallel to these works, we have started the user program on AMATERAS from December 2009 and we are getting scientific results from our spectrometer. In this presentation, we will report the current status of AMATERAS including the results of performance tests and some of examples of scientific outputs.
Toriihara, Makoto*; Maruyama, Makoto*; Suzuki, Kenichiro*; Namiki, Kazuto*
JNC TJ7400 2005-034, 179 Pages, 2004/02
JNC-TJ7400-2005-034.PDF:31.02MB
Elucidation of the physichal process leading to brittle failure in crystalline rocks and modeling its mechanism is of fundamental importance in evaluating the mechanical and hydraulic properties of EDZ. In this study, Granitic rock columns and plates with circular opening were subjected to triaxial compression and tension tests and measured elastic wave velocity and resisitivity to analyze nucleation and growth of microcracks. The following conclusions were important to note that: (1)During 90% to 100% stress levels to failure stress, it appear that cracks grew on their size but no cracks were nucleated. (2)It was demonstrated that crack tensor F
was closely related the second rank tensor V which was determined by measuring elastic wave velocity on at least six direction. (3)The applicability of numerical analysis model based on the micromechanics was introduced. This could be considered the mechanism of the damage growth (microcrack growth) and the interaction among microcracks. (4)On the experiment of Granitic rock plates with circular opening, the process leading to brittle failure and damage growth of the rock around the opening were observed with AE monitoring and so on. (5)In order to evaluate the variety of permeability with the damage growth, it was showed that permeability tensor in terms of crack tensor gave the permeability change in stress history.
Toriihara, Makoto*; Maruyama, Makoto*; Kuwahara, T.*; Suzuki, Kenichiro*
JNC TJ7400 2005-032, 206 Pages, 2003/02
JNC-TJ7400-2005-032.PDF:29.17MB
Elucidation of the physical process leading to brittle failure in crystalline rocks and modeling its mechanism is of fundamental importance in evaluating the mechanical and hydraulic properties of EDZ. In this study, Granitic rock columns and plates with circular opening were subjected to triaxial compression and tension tests and measured elastic wave velocity and resisitivity to analyze nucleation and growth of microcracks. The following conclusions were important to note that: (1)During 90% to 100% stress levels to failure stress, it appear that cracks grew on their size but no cracks were nucleated. (2)It was demonstrated that crack tensor F was closely related the second rank tensor V which was determined by measuring elastic wave velocity on at least six direction. (3)The applicability of numerical analysis model based on the micromechanics was introduced. This could be considered the mechanism of the damage growth (microcrack growth) and the interaction among microcracks. (4)On the experiment of Granitic rock plates with circular opening, the process leading to brittle failure and damage growth of the rock around the opening were observed with AE monitoring and so on. (5)In order to evaluate the variety of permeability with the damage growth, it was showed that permeability tensor in terms of crack tensor gave the permeability change in stress history.
Miyahara, Tsuneaki*; Ishii, Hiroyoshi*; Takayama, Yasuhiro*; Hirose, Masaaki*; Maruyama, Kenichi*; Obu, Kenji*; Shinoda, Motoki*; Muro, Takayuki*; Saito, Yuji; Matsuda, Tatsuma*; et al.
Journal of the Physical Society of Japan, 70(10), p.2977 - 2981, 2001/10
Times Cited Count：6 Percentile：42.02(Physics, Multidisciplinary)no abstracts in English
Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya*; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.
no journal, ,
no abstracts in English
Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Hayashida, Hirotoshi; To, Kentaro; Yamagishi, Hideshi*; Katagiri, Masaki*; Sakasai, Kaoru; Maruyama, Ryuji; Mizusawa, Tazuko*; et al.
no journal, ,
Kubota, Masato; Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Oikawa, Kenichi; Yamazaki, Tatsuya*; Aizawa, Kazuya; et al.
no journal, ,
Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
In the vacuum vessel of ITER, the blanket modules will be handled by a huge robotic manipulator that travels on a rail which has been deployed into the vessel. This system is called the ITER blanket remote handling system. A robot vision system using two cameras was developed for rough positioning of that system. Previous testing confirmed that the manipulator satisfies the required positioning accuracy with that robot vision system. However, these tests also showed that camera calibration and edge detection take quite some time since precise camera positioning is needed to calibrate the cameras, and parameters need to be adjusted during operations for edge detection. To improve camera calibration, software image transformation to correct the misalignment of cameras was adopted. Using this method, positioning of cameras does not affect accuracy of the robot vision system, and thus precise positioning of cameras is not necessary. To improve edge detection, we adopted smaller apertures for a wider depth of field, edge dilation for connecting edges, and the Sobel operator for detecting the edges of the modules. These methods make edge detection robust and the adjustment of parameters unnecessary. Through testing we confirmed that these methods make the robot vision system more efficient.
Takeda, Nobukazu; Tanigawa, Hisashi; Ueno, Kenichi; Maruyama, Takahito; Noguchi, Yuto; Kakudate, Satoshi
no journal, ,
In the vacuum vessel of the ITER, dose rate is very high (250 Gy/h) even during the plasma shutdown. Therefore, in-vessel components such as blanket and divertor must be maintained by remote handling. Procurement of the remote handling system of the blanket is allocated to Japan and the JAEA is performing the final design of it toward handover to the ITER Organization scheduled in 2020. This report shows progress of the final design activity. In the final design, the major part of the systems are more detailed and the tools for welding and cutting of blanket pipes are newly designed. In the same time, feasibility of operation scenario is confirmed by system analyses such as the reliability, availability, maintainability and inspectability analysis and structural analysis. By these activities, it is confirmed that the main components whose manufacturing contract will be awarded in this year can be fabricated without any concern and will be handed over to the ITER Organization in 2020 as planned.
Saito, Makiko; Maruyama, Takahito; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
In ITER, after plasma operation, The Blanket Remote Handling System (BRHS) will be installed in the vacuum vessel and it will remove and install the shield blanket module. BRHS will undergo hands-on maintenance in the maintenance area after the exchange of the shield blanket module. Since BRHS will be contaminated the radioactive dust in the vacuum vessel, the workers will be exposed by radioactive dust. In this study, potential contaminated areas and their respective dose rates from the BRHS using MCNP5 code to assess the exposure of maintenance workers. The assessment was performed using 3 types of equipment, vehicle manipulator, combination of cable handling and rail support, and sliding beam, which are installed in vacuum vessel or port. The dose calculations used the nuclides Ta-182 and W-181 and the dose was calculated from each of the 20 points spaced evenly around the equipment. As a result, there are some local points with high dose rates, which are exceed the target of acceptable dose limit for hands-on work in ITER (5 Sv/h) in vehicle manipulator and combination of cable handling and rail support. To decrease the dose rate, lead blocks were used for shielding and as a result, the dose rate decreased to around 2.5 Sv/h using 5 mm and 10 mm lead shielding.
Mizutani, Kotaro*; Hirouchi, Daisuke*; Matsuta, Nobuhisa*; Ishiyama, Tatsuya*; Sugito, Nobuhiko*; Yasue, Kenichi*; Takeshita, Yoshihiro*; Fujita, Natsuko; Sawa, Sho*; Doke, Ryosuke*; et al.
no journal, ,
no abstracts in English
Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.
no journal, ,
no abstracts in English
