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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
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：19.71(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.
Maruyama, Takahito; Noguchi, Yuto
Nihon Robotto Gakkai-Shi, 33(6), p.416 - 420, 2015/07
no abstracts in English
Noguchi, Yuto; Maruyama, Takahito; Takeda, Nobukazu; Kakudate, Satoshi
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 9 Pages, 2015/05
This paper reports the seismic analysis of the ITER Blanket RH system (BRHS) during blanket module handling operation. Since the BRHS, which is composed of the articulated rail and the vehicle manipulator, which travels on the rail deployed in the vacuum vessel in the toroidal direction, has various configurations and the rail system has flexibility, evaluation of dynamic response of the system is of essential importance. Via parameter sensitivity study on position and posture of the vehicle manipulator, the most unfavorable configuration for each component of the BRHS has been specified by the modal and spectrum analyses with the global BRHS FE model. Then using the quasi-static equivalent loads on the individual components obtained by the global BRHS seismic analysis, the structural verifications of the structural members of the BRHS have been carried out with detailed partial FE models. The system seismic resistance of the BRHS to a safe shutdown earthquake was confirmed.
Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi
Plasma and Fusion Research (Internet), 10(Sp.2), p.3405010_1 - 3405010_4, 2015/02
Noguchi, Yuto; Anzai, Katsunori; Kozaka, Hiroshi; Aburadani, Atsushi; Kazawa, Minoru; Takeda, Nobukazu; Kakudate, Satoshi
Dai-31-Kai Nihon Robotto Gakkai Gakujutsu Koenkai Yokoshu (DVD-ROM), 2 Pages, 2013/09
Noguchi, Yuto; Maruyama, Takahito; Anzai, Katsunori; Kozaka, Hiroshi; Kazawa, Minoru; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
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.
Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Noguchi, Yuto; Maruyama, Takahito; Anzai, Katsunori; Takeda, Nobukazu; Kakudate, Satoshi
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no abstracts in English
Ueno, Kenichi; Tanigawa, Hisashi; Noguchi, Yuto; Inoue, Ryuichi; Anzai, Katsunori; Kazawa, Minoru; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
At the ITER blanket, there are cooling pipes for cooling. They will be cut and welded by dedicated tools. For the cooling pipe cutting, remaining the dust and swarf at the cooling pipe are prohibited and suitable cutting surface for rewelding are required. To implement these requirement, swage cutter cutting system were made as a mockup and tested for simulated cooling pipes. There were no cutting dust and suitable cutting surface by the swage cutter cutting system. For the blanket cooling pipe welding, relaxation for the positioning of welding groove, improvement for optical system durability of LASER welding are required. The mockup of LASER welding tool head were made and tested for simulated cooling pipes. As the result of welding condition improvement, relaxed welding condition with low sputter generation were taken. For the cooling pipe welding groove alignment, alignment tool was made and tested for correction of simulated cooling pipe misalignment. For less than 1.5mm of linear misalignment and 0.5 degree angular misalignment, required alignment accuracy were confirmed. Positioning accuracy and stability improvement at the tool operation were issued for the ITER blanket cooling pipe tool heads development.
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.
Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Saito, Makiko; Anzai, Katsunori; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Maruyama, Takahito; Noguchi, Yuto; Komai, Masafumi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Inoue, Ryuichi; Noguchi, Yuto; Maruyama, Takahito; Tanigawa, Hisashi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Komai, Masafumi; Anzai, Katsunori; Noguchi, Yuto; Saito, Makiko; Maruyama, Takahito; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
-ray Environment of ~250 Gy/hr in International Thermonuclear Experimental Reactor (ITER) requires a full remote maintenance of in-vessel components such as blanket modules. JAEA is carrying out development of radiation hard components for the ITER blanket remote handling system. The current status of the radiation hardness component development is presented.
Noguchi, Yuto; Maruyama, Takahito; Komai, Masafumi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Takeda, Nobukazu; Noguchi, Yuto; Maruyama, Takahito; Inoue, Ryuichi; Komai, Masafumi; Kozaka, Hiroshi; Tanigawa, Hisashi; Kakudate, Satoshi
no journal, ,
In general, nuclear fusion device requires remote maintenance system to avoid human access because of -ray emitted from structural material, which is activated by neutron of fusion reaction. The remote maintenance system was first introduced in the Joint European Torus (JET) which was constructed in UK based on international cooperation in Europe. The JET used so-called "Boom type" remote handling system which introduces articulated arm from a port. The arm is supported from the port with canti-levered and therefore the capacity is relatively low: 300 kg in JET. On the contrary, the ITER uses different type of remote handling system. The JT-60SA, which is under construction in Japan, also considers remote maintenance. This paper describes outline of remote maintenance systems for the international fusion experimental reactor, ITER.
