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Saito, Makiko; Kozaka, Hiroshi; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi; 1 of others*
Fusion Engineering and Design, 124, p.542 - 547, 2017/11
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：16.92(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; Anzai, Katsunori; Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi
Fusion Engineering and Design, 109-111(Part B), p.1502 - 1506, 2016/11
Tanigawa, Hisashi; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi
Fusion Engineering and Design, 98-99, p.1634 - 1637, 2015/10
This paper presents recent results of the laser welding tests where groove geometry was changed to expand the allowable initial gap. Additional material is required to avoid excess concavity caused by the initial gap between pipes. Generally wire fill is applied. However, this leads to additional complication in the remote handling tool. In the present study, the groove was machined to be partially thick instead of the filler wire. Firstly, plates with the partially thick grooves were welded to study preferable groove geometry and welding conditions. For the groove with additional metal 0.7 mm-thick and 4.0 mm-wide, the plates with the initial gap of 1.0 mm can be welded. Then the groove geometry and welding conditions were modified through the pipe welding tests. Thicker groove requires higher heat input, and increase of the heat input leads to burn through especially for the pipe welding. By the application of the additional metal 0.5 mm-thick and 2.5 mm-wide in the groove, allowable initial gap increased from 0.2 mm to 0.7 mm.
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
Maruyama, Takahito; Aburadani, Atsushi; Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka; Tesini, A.*
Fusion Engineering and Design, 89(9-10), p.2404 - 2408, 2014/10
Times Cited Count：10 Percentile：56.39(Nuclear Science & Technology)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：48.73(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, 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.
Noguchi, Yuto; Maruyama, Takahito; Anzai, Katsunori; 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.
Saito, Makiko; Anzai, Katsunori; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
Noguchi, Yuto; Maruyama, Takahito; Komai, Masafumi; Takeda, Nobukazu; Kakudate, Satoshi
no journal, ,
no abstracts in English
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.
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.
