Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 414

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Japan Atomic Energy Agency; Contribution to the decommissioning of the Fukushima Daiichi Nuclear Power Station and the reconstruction of Fukushima Prefecture at the Naraha center for Remote Control technology development

Morimoto, Kyoichi; Ono, Takahiro; Kakutani, Satomi; Yoshida, Moeka; Suzuki, Soichiro

Journal of Robotics and Mechatronics, 36(1), p.125 - 133, 2024/02

The Naraha Center for Remote Control Technology Development was established for the purpose of developing and verifying remote control equipment for promoting the decommissioning of the Fukushima Daiichi Nuclear Power Station and the external use of this center was started in 2016. The mission of this center is to contribute to the decommissioning of the Fukushima Daiichi Nuclear Power Station and for the reconstruction of Fukushima Prefecture. In this review, we describe the equipment related to the full-scale mock-up test, the component test for a remote-control device and the virtual reality system in this center. In addition, the case examples for usage of these equipment are introduced.

Journal Articles

Exhumation history of the Kurobe area, Hida Range, based on solidification ages and depths of the Pliocene-Quaternary plutons

Sueoka, Shigeru; Kawakami, Tetsuo*; Suzuki, Kota*; Kagami, Saya; Yokoyama, Tatsunori; Shibazaki, Bunichiro*; Nagata, Mitsuhiro; Yamazaki, Ayu*; Higashino, Fumiko*; King, G. E.*; et al.

Fisshion, Torakku Nyusureta, (36), p.1 - 3, 2023/12

no abstracts in English

JAEA Reports

Annual report for FY2021 on the activities of Naraha Center for Remote Control Technology Development (April 1, 2021 - March 31, 2022)

Akiyama, Yoichi; Shibanuma, So; Yanagisawa, Kenichi*; Yamada, Taichi; Suzuki, Kenta; Yoshida, Moeka; Ono, Takahiro; Kawabata, Kuniaki; Watanabe, Kaho; Morimoto, Kyoichi; et al.

JAEA-Review 2023-015, 60 Pages, 2023/09

JAEA-Review-2023-015.pdf:4.78MB

Naraha Center for Remote Control Technology Development (NARREC) was established in Japan Atomic Energy Agency to promote a decommissioning work of Fukushima Daiichi Nuclear Power Station (Fukushima Daiichi NPS). NARREC consists of a Full-scale Mock-up Test Building and Research Management Building. Various test facilities are installed in these buildings for the decommissioning work of Fukushima Daiichi NPS. These test facilities are intended to be used for various users, such as companies engaged in the decommissioning work, research and development institutions, educational institutions and so on. The number of NARREC facility uses was 84 in FY2021. We participated booth exhibitions and presentations on the decommissioning related events. Moreover, we also contributed to the development of human resources by supporting the 6th Creative Robot Contest for Decommissioning. As a new project, "Narahakko Children's Classroom" was implemented for elementary school students in Naraha Town. This report summarizes the activities of NARREC in FY2021, such as the utilization of facilities and equipment of NARREC, the development of remote-control technologies for supporting the decommissioning work, arrangement of the remote-control machines for emergency response, and training for operators by using the machines.

Journal Articles

Factors regulating the concentration of particulate iodine in coastal seawater

Sato, Yuhi*; Otosaka, Shigeyoshi*; Suzuki, Takashi; Nakanishi, Takahiro

Limnology and Oceanography, 68(7), p.1580 - 1594, 2023/07

 Times Cited Count:0 Percentile:65.24(Limnology)

To investigate the factors regulating the concentration of particulate iodine (PI) in seawater, it was measured in two Pacific coastal areas adjacent to Japan in two seasons along with parameters such as particulate organic carbon (POC) and nitrogen (PON), dissolved iodine (DI), and phytoplankton pigments. The dataset was divided in three groups namely, lower (Group A), average (Group B), and higher (Group C) atomic ratios of PI to POC (I/C). The three groups were characterized by phytoplanktonic physiological states as highly productive, steady, and senescent states, respectively. Based on the finding that PI production is associated with the phytoplankton physiological state, the seasonal and regional differences in PI concentration and I/C in the observation areas were consistently explained. Finally, we suggest that the phytoplanktonic physiological state is one of the vital factors regulating the PI concentration in seawater.

Journal Articles

Reducing the effect of noise generated from stepper motor for H0 collimator in J-PARC RCS

Fujiyama, Hiroki*; Takahashi, Hiroki; Okabe, Kota; Ito, Yuichi*; Hatakeyama, Shuichiro; Suzuki, Takahiro*; Otsu, Satoru*; Yamakawa, Ryuto*

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.529 - 531, 2023/01

Stepper motors are used for mechanical drive in collimators and wire scanner monitors of J-PARC accelerators. Many of these drive unit hardware have been used since the beginning of J-PARC construction, and it is necessary to take measures against aging deterioration. Therefore, we started updating the motor and control system from around 2017. However, when the stepper motor was updated to the current product in the RCS H0 collimator, a malfunction occurred. This is because the drive unit control system cannot correctly recognize the state of the LS (limit switch) due to the noise generated by the motor driver, which hinders the operation. When the noise generated from the old and new stepper motors was measured in a simple test environment for confirmation, it was found that the current product was clearly larger. As a countermeasure, when the wiring of the stepper motor, which was bundled in a single multi-core cable, was separated into separate cables for the power system and LS signal system, the noise level was reduced to about 1/10 and normal operation was restored. I was able to. In this case, we report on noise countermeasures for the RCS H0 collimator drive unit.

Journal Articles

Solidification pressures and ages recorded in mafic microgranular enclaves and their host granite; An Example of the world's youngest Kurobegawa granite

Suzuki, Kota*; Kawakami, Tetsuo*; Sueoka, Shigeru; Yamazaki, Ayu*; Kagami, Saya; Yokoyama, Tatsunori; Tagami, Takahiro*

Island Arc, 31(1), p.e12462_1 - e12462_15, 2022/09

 Times Cited Count:1 Percentile:37.23(Geosciences, Multidisciplinary)

Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

 Times Cited Count:3 Percentile:80.29(Nuclear Science & Technology)

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Update of MPS modules for J-PARC linac and RCS, 2

Takahashi, Hiroki; Suzuki, Takahiro*; Ishiyama, Tatsuya*; Ito, Yuichi*

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.914 - 917, 2021/10

In the event of an abnormal situation, a machine protection system (MPS) that immediately inhibits the beam is indispensable to minimize the damage and the radioactivation by beam loss. The existing MPS was developed during the construction period, and there are many MPS modules that have been used from the beginning of J-PARC operation, Therefore, as a measure against aging, we started designing, manufacturing and updating the new MPS module in 2018. In this paper, the specifications and the results of performance test about the newly designed and manufactured the MPS signal aggregation module and the E/O converter module will be described.

Journal Articles

High-temperature antiferromagnetism in Yb based heavy fermion systems proximate to a Kondo insulator

Suzuki, Shintaro*; Takubo, Ko*; Kuga, Kentaro*; Higemoto, Wataru; Ito, Takashi; Tomita, Takahiro*; Shimura, Yasumichi*; Matsumoto, Yosuke*; Bareille, C.*; Wadachi, Hiroki*; et al.

Physical Review Research (Internet), 3(2), p.023140_1 - 023140_12, 2021/05

We report our experimental discovery of the transition temperature reaching 20 K in a Yb-based compound at ambient pressure. The Mn substitution at the Al site in an intermediate valence state of $$alpha$$-YbAlB$$_4$$ not only induces antiferromagnetic transition at a record high temperature of 20 K but also transforms the heavy-fermion liquid state in $$alpha$$-YbAlB$$_4$$ into a highly resistive metallic state proximate to a Kondo insulator.

Journal Articles

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.

Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04

AA2020-0724.pdf:2.05MB

 Times Cited Count:1 Percentile:18.34(Chemistry, Multidisciplinary)

We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

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:30 Percentile:96.87(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 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$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.

Journal Articles

$$omega N$$ scattering length from $$omega$$ photoproduction on the proton near the reaction threshold

Ishikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.

Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05

Journal Articles

Development of a beam window protection system for the J-PARC Linac

Takahashi, Hiroki; Hatakeyama, Shuichiro; Sawabe, Yuki; Miyao, Tomoaki*; Ishiyama, Tatsuya*; Suzuki, Takahiro*

Journal of Physics; Conference Series, 1350, p.012142_1 - 012142_5, 2019/12

 Times Cited Count:0 Percentile:0.06

At the J-PARC Linac, beam conditioning and study are performed using beam dumps (BDs). To be a partition with the high vacuum section, a beam window (material Ni, 0.38 mm thick, mirror-shape) is installed upstream of the BD along the beam line. Beams that can be accepted by the beam window are about 1/50 or less of rated beam according to thermal evaluation and experience. Therefore, when using a beam dump, it is necessary not to exceed this tolerance. In a 2018 beam study, the beam e that exceeded tolerance was incident on the 0-degree dump due to human error, and the beam window was cracked. Then, this has revealed the need for protection of the beam window by hardware. Therefore, based on the existing system for monitoring the per-hour beam amount, we began to develop a system to monitor one shot beam and one second beam amount. And, we succeeded in implementing a system that protects the beam window by monitoring the beam in a short time (one shot, and for one second). In addition, the performance tests using actual beams were performed, and it was confirmed that the developed system had sufficient performance requirements to protect the beam window.

Journal Articles

Update of MPS modules for J-PARC Linac and RCS

Takahashi, Hiroki; Hayashi, Naoki; Nishiyama, Koichi*; Suzuki, Takahiro*; Ishiyama, Tatsuya*

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.271 - 274, 2019/07

In the event of an abnormal situation, a machine protection system (MPS) that immediately inhibits the beam is indispensable to minimize the damage and the radioactivation by beam loss. The existing MPS was developed during the construction period of the J-PARC. Then, the system has been working stably for more than ten years. On the other hand, since there are many MPS modules that have been used from the beginning of J-PARC operation, it is important to systematically proceed with updating (replacement) of modules as a measure against aging of MPS. However, the main components of the existing MPS module have been discontinued. Therefore, it is indispensable to redesign the MPS modules in consideration of improvement such as the compatibility with existing modules and the miniaturization. In this paper, the development status of the new module and the update plan of MPS for Linac and RCS are detailed.

Journal Articles

Development of a beam window protection system for the J-PARC Linac

Takahashi, Hiroki; Hatakeyama, Shuichiro; Sawabe, Yuki; Miyao, Tomoaki*; Ishiyama, Tatsuya*; Suzuki, Takahiro*

Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.3886 - 3889, 2019/06

At the J-PARC Linac, beam conditioning and study are performed using beam dumps (BDs). To be a partition with the high vacuum section, a beam window (material Ni, 0.38 mm thick, mirror-shape) is installed upstream of the BD along the beam line. Beams that can be accepted by the beam window are about 1/50 or less of rated beam according to thermal evaluation and experience. Therefore, when using a beam dump, it is necessary not to exceed this tolerance. In a 2018 beam study, the beam e that exceeded tolerance was incident on the 0-degree dump due to human error, and the beam window was cracked. Then, this has revealed the need for protection of the beam window by hardware. Therefore, based on the existing system for monitoring the per-hour beam amount, we began to develop a system to monitor one shot beam and one second beam amount. And, we succeeded in implementing a system that protects the beam window by monitoring the beam in a short time (one shot, and for one second). In addition, the performance tests using actual beams were performed, and it was confirmed that the developed system had sufficient performance requirements to protect the beam window.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:233 Percentile:99.74(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Distribution and fate of $$^{129}$$I in the seabed sediment off Fukushima

Otosaka, Shigeyoshi; Sato, Yuhi*; Suzuki, Takashi; Kuwabara, Jun; Nakanishi, Takahiro

Journal of Environmental Radioactivity, 192, p.208 - 218, 2018/12

AA2017-0744.pdf:1.17MB

 Times Cited Count:12 Percentile:48.82(Environmental Sciences)

From August 2011 to October 2013, the concentration of iodine-129 ($$^{129}$$I) in the seabed sediment collected from 26 stations located within 160 km from the Fukushima Daiichi Nuclear Power Plant was estimated. The concentrations of $$^{129}$$I in seabed sediment off Fukushima in 2011 ranged between 0.02 and 0.45 mBq/kg. Although iodine is a biophilic element, the accident-derived radioiodine negligibly affects the benthic ecosystem. Until October 2013, a slightly increased activity of $$^{129}$$I in the surface sediment in the shelf-edge region (bottom depth: 200-400 m) was observed. The increase of the $$^{129}$$I concentrations in the shelf-edge sediments was affected by the (1) transport of $$^{129}$$I-bound particles from the land through rivers and (2) re-deposition of $$^{129}$$I desorbed from the contaminated coastal sediment to the shelf-edge sediments, which were considered to be dominant processes.

Journal Articles

Standardization of stepping motor control system in J-PARC Linac and RCS

Takahashi, Hiroki; Sawabe, Yuki; Suzuki, Yasuo*; Suzuki, Takahiro*; Kawase, Masato*

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1105 - 1108, 2018/08

J-PARC Linac and RCS Profile Monitor and etc. are devices consisting of moving parts and driving part. In these devices, in order to move the movable part to an appropriate position without damaging it, proper control of the stepping motor used for the driving part is important. Many of the control system hardware of these drive units are used since the early days of J-PARC operation, and there is concern about malfunctions due to aging. In addition, since both VME and PLC are used as controllers, it is necessary to prepare spare parts of both control equipment in maintenance and management. Besides, the control logic differs depending on the kind of controller, VME or PLC. Therefore, maintainability of both hardware and software is an important issue. Then, we decided to proceed with updating the drive unit control system which standardized control system hardware and software. In this paper, the standardization of stepping motor control system in Linac and RCS is detailed.

Journal Articles

Improvement of motor control system in J-PARC linac and RCS

Takahashi, Hiroki; Miura, Akihiko; Sawabe, Yuki; Yoshimoto, Masahiro; Suzuki, Takahiro*; Kawase, Masato*

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.2180 - 2182, 2018/06

The stepping motor control system used in the profile monitor and RCS collimator of J-PARC is configured by VME-based. Most of these pieces of control equipment are in use for more than 10 years. Therefore, countermeasures against aging of equipment are necessary. In addition, it is necessary to implement countermeasures against malfunction of the control system, which is thought to be caused by radiation. In 2016, a malfunction occurred in the motor control system of the RCS collimator. Taking this as a starting point, we began developing a motor control system that can ensure equipment safety even if a malfunction occurs. In this paper, we show the inference of the cause of this malfunction and present details of the developed high-safety motor control system.

Journal Articles

Examination of evaluation method for fault activity based on morphological observation of fault planes

Tanaka, Yoshihiro*; Kametaka, Masao*; Okazaki, Kazuhiko*; Suzuki, Kazushige*; Seshimo, Kazuyoshi; Aoki, Kazuhiro; Shimada, Koji; Watanabe, Takahiro; Nakayama, Kazuhiko

Oyo Chishitsu, 59(1), p.13 - 27, 2018/04

This paper aims to develop a methodology for understanding the fault activity by observing exposed fault planes without covering younger strata. Based on purpose, faults developed in relatively homogeneous rocks such granitic types are investigated as follows; Gosuke Dam upstream outcrop of Gosukebashi Fault and Funasaka-nishi outcrop of Rokkou Fault were selected for the study of an active fault; and K-3 outcrop of Rokkou Houraikyo Fault was chosen for a non-active fault.

414 (Records 1-20 displayed on this page)