Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi
Materials Transactions, 63(4), p.538 - 544, 2022/04
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)The time dependence of the corrosion behavior of tantalum (Ta), which is used in nuclear fuel reprocessing equipment, in sodium hydroxide (NaOH) solutions was investigated by immersion tests, and the mechanism of the time dependence was examined via surface observations and electrochemical measurements. The immersion tests were conducted at room temperature with NaOH concentrations ranging from 1 to 7 mol/L for immersion periods of 24 to 168 h. The corrosion rate increased with the NaOH concentration but peaked with the immersion period and then decreased. The time to peak of the corrosion rate was shorter with higher NaOH concentration. The X-ray diffraction (XRD) patterns and Raman spectra of the surfaces of the specimens immersed in the 7 mol/L NaOH solution for more than 48 h showed Na
Ta
O
formation. The polarization resistance decreased with immersion time for all NaOH concentrations up to about 24 h after immersion. Thereafter, the polarization resistance increased with immersion time in 7 mol/L NaOH solution and remained almost constant in the other NaOH concentrations. Findings suggested that the change in the corrosion rate was affected by the film formation during immersion, since the time dependence of the polarization resistance and the sum of film resistance and charge transfer resistance had the same tendencies. The precipitation film was mainly NaTaO formed by the dissolution of the passivity film on Ta.
Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi
Zairyo To Kankyo, 70(6), p.192 - 198, 2021/06
The time dependence of corrosion behavior on tantalum used in nuclear fuel reprocessing equipment in sodium hydroxide solution was investigated by immersion corrosion tests, and the mechanism of aging change was discussed from surface observations and electrochemical measurements. The immersion tests were carried out at room temperature with NaOH concentrations ranging from 1 to 7 mol/L and immersion times ranging from 24 to 168 hr, respectively. The corrosion rate increased with NaOH concentration, but peaked with immersion time and then decreased. The time to peak of corrosion rate was shorter with higher NaOH concentration. The SEM observations and Raman analysis at the surface of the specimens that were cleaned and weighed after the immersion test did not show any film formation. On the other hand, the polarization resistance showed a constant value or an increase after a decrease immediately after immersion. It is suggested that the change in corrosion rate is affected by the formation of film by immersion, since the value of polarization resistance is almost the same as the sum of film resistance and charge transfer resistance. The film was considered to be mainly NaTaO formed by the dissolution of Ta.
Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Obayashi, Hironari; Watanabe, Nao; Ohdaira, Naoya*; Kinoshita, Hidetaka; Yamaki, Kenichi*; Kita, Satoshi*; Yoshimoto, Hidemitsu*; et al.
JPS Conference Proceedings (Internet), 33, p.011041_1 - 011041_6, 2021/03
An Accelerator Driven System (ADS) for waste transmutation investigated in JAEA employs lead-bismuth eutectic (LBE) as a neutron production target material and coolant. The neutrons are to be produced via the spallation with 1.5 GeV proton beam injection. As materials irradiation data are important for ADS development, JAEA plans to construct an irradiation facility with LBE neutron production target in J-PARC. There are many technical issues on LBE for practical use. In JAEA, various R&Ds are being carried out. Concerning corrosion study, conditioning operation and functional tests of OLLOCHI started. Oxygen concentration control technology has also developing. In the large scale LBE loop experiment, the operation for steady state and transient experiments was performed by using IMMORTAL. In the area of instrument, development of ultrasonic flow meter and freeze seal valve are progressing as a key technology for the LBE loop system. Investigation of behavior of impurities in LBE, which is important for design of the irradiation facility, started. In this paper, the status of the LBE studies and experimental plan will be presented.
Magome, Hirokatsu; Iimura, Koichi; Matsui, Yoshinori
JAEA-Technology 2020-022, 32 Pages, 2021/02
JAEA-Technology-2020-022.pdf:4.04MB
Among the canal underwater equipment of HR-1, seismic evaluations of the canal side wall parts and the canal bottom surface parts were carried out for the insertion device, take-out device and decay tank. As a result, it was confirmed that the equipments have sufficient seismic resistances because the maximum stress of the canal side wall joint, the bolt portion of the canal bottom joint, and the fillet weld are within the allowable stress.
Horiguchi, Kenichi
Gijutsushi, 30(4), p.8 - 11, 2018/04
The verification activity and training of operation in the Fukushima-Daiichi Nuclear Power Station are more important than another Nuclear Power Station. At the JAEA Naraha Remote Technology Development Center, it has being carried out the development work to apply to the decommissioning work by using the full sized mock up and VR system which is built based on location surveying data of inside the reactor building. It is able to contribute to the decommissioning more reliably and efficiently.
Kawabata, Kuniaki; Mori, Fumiaki*; Shirasaki, Norihito; Tanifuji, Yuta; Hanari, Toshihide
Proceedings of 2017 IEEE/SICE International Symposium on System Integration (SII 2017), p.450 - 455, 2018/02
This paper describes the test facilities and experimental environments for supporting the decommissioning of the nuclear facilities especially Fukushima Daiichi Nuclear Power Station by remote operation. Naraha Remote Technology Development Center of Japan Atomic Energy Agency is an institution for such purpose. Mock-up staircase, robot testing pool and motion capture arena are already installed and full service and support began from April, 2016. We are also designing and developing some experimental environment for remotely operated robots for nuclear decommissioning. In this paper, we describe current status and development of test facilities of Naraha Remote Technology Development Center, Japan Atomic Energy Agency.
Kawabata, Kuniaki; Suzuki, Kenta; Isowa, Mitsuru*; Horiuchi, Kazunori; Ito, Rintaro
Proceedings of 14th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI 2017) (USB Flash Drive), p.561 - 564, 2017/06
This paper describes the current status of the development of a simulation system for remotely operated robots. The system will be used for operator proficiency training and robot performance verification. Our purpose for developing this system is to contribute to decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The simulator system was designed using Choreonoid, a simulator development tool. The effects of view disturbances, communication failures, and so on are extended functions that are implemented on the simulator. The effects of water submergence on the physical behavior of underwater robots are also implemented. In this paper, we introduce the prototype of the robotic simulator system with the newly implemented extended functions. Some examples of system output are shown.
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.
Ohira, Shigeru; Luo, G.; Nakamura, Hirofumi; Shu, Wataru; Kitamura, Kazunori*; Nishi, Masataka
Fusion Science and Technology, 48(1), p.621 - 624, 2005/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)A new conceptual design of a tritium permeation test module assembly was developed for demonstration tests using a strong plasma source constructed in TPL for simulation of practical tritium permeation in the real plasma facing components and validation of the models and codes for evaluation of tritium permeation. The target module, to be irradiated by the high flux plasma beam, consists of a multi-layer structure of a plasma facing material plate and a copper substrate with pressurized coolant cavity. Tests using a preliminary model of the target module has been performed to verify thermal and mechanical behavior of the bonded structure and to assess its structural integrity focused on the bonded interface under the cyclic heat loads. After the heat load testing, no visible defect and crack was observed around the bonded interfaces with magnifying glass, and its structural integrity was verified. Also the first tests using tritium plasma at TSTA/LANL with the preliminary model was performed and process to measured tritium permeated was established.
Suzuki, Satoshi; Ueda, Yoshio*
Nihon Genshiryoku Gakkai-Shi, 47(4), p.266 - 271, 2005/04
no abstracts in English
Hasegawa, Kazuo
Proceedings of 34th ICFA Advanced Beam Dynamics Workshop on High Power Superconducting Ion, Proton and Multi-Species Linacs (HPSL 2005) (Internet), 7 Pages, 2005/00
no abstracts in English
Kurihara, Ryoichi
JAERI-Tech 2004-052, 39 Pages, 2004/07
The problems in the thermal structural design of the plasma facing component such as the blanket first wall and the divertor plate which receives very high heat flux were examined in the design of the fusion power reactors. Compact high fusion power reactor must give high heat flux and high-speed neutron flux from the plasma to the first wall and the divertor plate. In this environmental situation, the micro cracks should be generated in material of the first wall. Structural integrity of the first wall would be very low during the operation of the reactor, if those micro-cracks grow in a crack having significant size by the fatigue or the creep. The crack penetration in the first wall can be a factor which threatens the safety of the fusion power reactor. This paper summarizes the problems on the structural integrity in the first wall made of the SiC/SiC composite material or the ferritic steel.
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
Times Cited Count：7 Percentile：22.88(Physics, Fluids & Plasmas)no abstracts in English
Tsutsumi, Hideaki*; Ebisawa, Katsumi*; Yamada, Hiroyuki*; Shibata, Katsuyuki; Fujimoto, Shigeru*
Nihon Zairyo Gakkai JCOSSAR 2003 Rombunshu, p.829 - 836, 2003/11
no abstracts in English
Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Torii, Yoshikatsu; Hino, Ryutaro; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 1, p.125 - 133, 2003/07
no abstracts in English
Plasma Heating Laboratory
JAERI-Review 2003-010, 246 Pages, 2003/03
JAERI-Review-2003-010.pdf:26.46MB
no abstracts in English
Hanzawa, Yukiko; Magara, Masaaki; Watanabe, Kazuo; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Gunji, Katsubumi*; Sakurai, Satoshi; Takano, Seinojo*; Usuda, Shigekazu; et al.
Journal of Nuclear Science and Technology, 40(1), p.49 - 56, 2003/01
Times Cited Count：4 Percentile：31.59(Nuclear Science & Technology)The JAERI has established a cleanroom facility with cleanliness of ISO Class 5: the Clean Laboratory for Environmental Analysis and Research (CLEAR). It was designed to be used for the analysis of nuclear materials in environmental samples for the safeguards, the Comprehensive Nuclear-Test-Ban Treaty verification and research on environmental sciences. The CLEAR facility was designed to meet double conflicting requirements of a cleanroom and for handling of nuclear materials according to Japanese regulations, i.e., to avoid contamination from outside and to contain nuclear materials inside the facility. This facility has been intended to be used for wet chemical treatment, instrumental analysis and particle handling. A fume-hood to provide a clean work surface for handling of nuclear materials was specially designed. The performance of the cleanroom and analytical background in the laboratory are discussed. It can be concluded that the CLEAR facility enables analysis of ultra trace amounts of nuclear materials at the sub-picogram level in environmental samples.
Matsuda, Makoto; Takeuchi, Suehiro; Yoshida, Tadashi; Hanashima, Susumu; Fujii, Yoshio*
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.170 - 172, 2003/00
no abstracts in English
Saito, Shigeru; Fukaya, Kiyoshi*; Ishiyama, Shintaro; Sato, Kazuyoshi
Journal of Nuclear Materials, 307-311(2), p.1542 - 1546, 2002/12
Times Cited Count：37 Percentile：89.13(Materials Science, Multidisciplinary)no abstracts in English
