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Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Kimura, Hideo; Hikasa, Naoki*; Kugenuma, Yuji*; Doi, Toshiharu*; Kikuchi, Yoshitaka*
JAEA-Technology 2019-004, 25 Pages, 2019/05
JAEA-Technology-2019-004.pdf:3.02MB
JAEA has developed the "Financial and contract information system" for effective and efficient accomplishment of the mission-critical tasks. Because the development of the next system was necessary with the end in the support time limit of the current system, we carried out the development of the next system in 2018. While the addition of the electronic approval function or the adoption of the latest package software largely performed a functional enhancement until now by applying distributed systems construction technique based on the separation procurement that we devised progressively, in development, we extremely realized procurement with the low cost.
/Md
reduction potential studied with flow electrolytic chromatographyToyoshima, Atsushi; Li, Z.*; Asai, Masato; Sato, Nozomi; Sato, Tetsuya; Kikuchi, Takahiro; Kaneya, Yusuke; Kitatsuji, Yoshihiro; Tsukada, Kazuaki; Nagame, Yuichiro; et al.
Inorganic Chemistry, 52(21), p.12311 - 12313, 2013/11
Times Cited Count：5 Percentile：23.58(Chemistry, Inorganic & Nuclear)The reduction behavior of mendelevium (Md) was studied using a flow electrolytic chromatography apparatus. By applying appropriate potentials on the chromatography column, the more stable Md is reduced to Md. The reduction potential of the Md + e
Md couple was determined to be -0.16
0.05 V vs. a normal hydrogen electrode.
SO
/HNO
mixed solutionLi, Z.*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro; Sch
del, M.; Pershina, V.*; et al.
Radiochimica Acta, 100(3), p.157 - 164, 2012/03
Times Cited Count：13 Percentile：69.01(Chemistry, Inorganic & Nuclear)Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Li, Z.; Ishii, Yasuo; Tome, Hayato*; Sato, Tetsuya; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.
Chemistry Letters, 38(11), p.1084 - 1085, 2009/10
Times Cited Count：15 Percentile：48.93(Chemistry, Multidisciplinary)We report on the characteristic anion-exchange behavior of the superheavy element dubnium (Db) with atomic number Z = 105 in HF/HNO solution at the fluoride ion concentration [F] = 0.003 M. The result clearly demonstrates that the fluoro complex formation of Db is significantly different from that of the group-5 homologue Ta in the 6th period of the periodic table while the behavior of Db is similar to that of the lighter homologue Nb in the 5th period.
Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.
Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12
Times Cited Count：17 Percentile：72.86(Nuclear Science & Technology)no abstracts in English
Kawai, Mikito; Akino, Noboru; Ikeda, Yoshitaka; Ebisawa, Noboru; Honda, Atsushi; Kazawa, Minoru; Kikuchi, Katsumi; Mogaki, Kazuhiko; Noto, Katsuya; Oshima, Katsumi; et al.
JAEA-Technology 2008-069, 32 Pages, 2008/10
JAEA-Technology-2008-069.pdf:6.75MB
The neutral beam injection system for JT-60U consists of positive-ion based type(P-NBI) and negative-ion based type(N-NBI). The reionization losses of neutral beams in the drift ducts of both P-NBI and N-NBI are estimated using the data of ambient pressure and gas flow rate into the beamlines. This system was not enough to obtain detail injection power for a long pulse operation. Modifications of the system to obtain reionization loss for a long pulse operation have been conducted. The new system has a capability to measure the pressures of drift duct during operation. The system can calculate the reionization loss automatically during the pulse from the measured pressure. More acurate injection power can be obtained by this new system.
Ikeda, Yoshitaka; Hanada, Masaya; Kamada, Masaki; Kobayashi, Kaoru; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Inoue, Takashi; Honda, Atsushi; Kawai, Mikito; et al.
IEEE Transactions on Plasma Science, 36(4), p.1519 - 1529, 2008/08
Times Cited Count：12 Percentile：41.25(Physics, Fluids & Plasmas)The JT-60SA N-NBI system is required to inject 10 MW for 100 s at 500 keV. Three key issues should be solved for the JT-60SA N-NBI ion source. One is to improve the voltage holding capability. Recent R&D tests suggested that the accelerator with a large area of grids may need a high margin in the design of electric field and a long time for conditioning. The second issue is to reduce the grid power loading. It was found that some beamlets were strongly deflected due to beamlet-beamlet interaction and strike on the grounded grid. The grids are to be designed by taking account of beamlet-beamlet interaction in three-dimensional simulation. Third is to maintain the D- production for 100 s. A simple cooling structure is proposed for the active cooled plasma grid, where a key is the temperature gradient on the plasma grid for uniform D- production. The modified N-NBI ion source will start on JT-60SA in 2015.
Kikuchi, Katsumi; Akino, Noboru; Ebisawa, Noboru; Ikeda, Yoshitaka; Seki, Norikazu*; Takenouchi, Tadashi; Tanai, Yutaka
JAEA-Technology 2008-034, 25 Pages, 2008/04
JAEA-Technology-2008-034.pdf:3.7MB
The control system for auxiliary pumping facility and primary water cooling facility in JT-60 NBI was updated. To realize the cost reduction, the control system with many input and outputs of 2000 was updated by JAEA itself using commercial Programmable Logic Controllers (PLC's). JAEA also made software with 3600 ladder lines by JAEA itself based on commercial basic programs. In addition to the simple replacement of the hardware and software, the function of remote operation has been newly added. At present, the auxiliary pumping facility and the primary water cooling facility have been stably operated without troubles. The remote operation enables to collect the detailed information on the trouble more easily, resulting in a quick countermeasure for the trouble.
Honda, Atsushi; Okano, Fuminori; Oshima, Katsumi; Akino, Noboru; Kikuchi, Katsumi; Tanai, Yutaka; Takenouchi, Tadashi; Numazawa, Susumu*; Ikeda, Yoshitaka
Fusion Engineering and Design, 83(2-3), p.276 - 279, 2008/04
Times Cited Count：11 Percentile：59.16(Nuclear Science & Technology)The control system of the cryogenic facility in the JT-60 NBI system has been renewed by employing the PLC (Programmable Logic Controller) and SCADA (Supervisory Control And Data Acquisition) system. The original control system was constructed about 20 years ago by specifying the DCS (Distributed Control System) computer to deal with 400 feedback loops. Recently, troubles on this control system have increased due to its aged deterioration. To maintain a high reliability of the cryogenic facility, a new control system has been intended with PLC and SCADA system. By optimizing the function blocks and connecting them in the FBD language, the feedback loops in the new control system have been successfully replaced from DCS to PLC without software developer. At present, the new control system has worked well. This is the first application of the marketable PLC to the actual system with feedback loops of 
400 produced by the user itself.
ion beams in the JT-60 negative ion sourceHanada, Masaya; Kamada, Masaki; Akino, Noboru; Ebisawa, Noboru; Honda, Atsushi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Mogaki, Kazuhiko; et al.
Review of Scientific Instruments, 79(2), p.02A519_1 - 02A519_4, 2008/02
Times Cited Count：6 Percentile：32.32(Instruments & Instrumentation)A long pulse production of high-current, high-energy D ion beams was studied in the JT-60U negative ion source that was designed to produce 22 A, 500 keV D ion beams. Prior to the long pulse production, the short pulse beams were produced to examine operational ranges for a stable voltage holding capability and an allowable grid power loading. From a correlation between the voltage holding capability and a light intensity of cathodoluminescence from the insulator made of Fiber Reinforced Plastic insulator, the voltage holding was found to be stable at 
340 kV where the light was sufficiently suppressed. The grid power loading for the long pulse operation was also decreased to the allowable level of 1 MW without a significant reduction of the beam power by tuning the extraction voltage (Vext) and the arc power (Parc). These allow the production of 30 A D ion beams at 340 keV from two ion sources at Vacc = 340 kV. The pulse length was extended step by step, and finally reached up to 21 s, where the beam pulse length was limited by the surface temperature of the beam scraper without water cooling. The D ion beams were neutralized to via a gas cell, resulting in a long pulse injection of 3.2 MW D
beams for 21 s. This is the first long injection of 20 s in a power range of 3 MW.
Ikeda, Yoshitaka; Akino, Noboru; Ebisawa, Noboru; Hanada, Masaya; Inoue, Takashi; Honda, Atsushi; Kamada, Masaki; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; et al.
Fusion Engineering and Design, 82(5-14), p.791 - 797, 2007/10
Times Cited Count：22 Percentile：80.64(Nuclear Science & Technology)Modification of JT-60U to a superconducting device (so called JT-60SA) has been planned to contribute to ITER and DEMO. The NBI system is required to inject 34 MW for 100 s. The upgraded NBI system consists of twelve positive ion based NBI (P-NBI) units and one negative ion based NBI (N-NBI) unit. The injection power of the P-NBI units are 2 MW each at 85 keV, and the N-NBI unit will be 10 MW at 500 keV, respectively. On JT-60U, the long pulse operation of 30 s at 2 MW (85 keV) and 20 s at 3.2 MW (320 keV) have been achieved on P-NBI and N-NBI units, respectively. Since the temperature increase of the cooling water in both ion sources is saturated within 20 s, further pulse extension up to 100 s is expected to mainly modify the power supply systems in addition to modification of the N-NBI ion source for high acceleration voltage. The detailed technical design of the NBI system for JT-60SA is presented.
Hanada, Masaya; Ikeda, Yoshitaka; Kamada, Masaki; Kikuchi, Katsumi; Komata, Masao; Mogaki, Kazuhiko; Umeda, Naotaka; Usui, Katsutomi; Grisham, L. R.*; Kobayashi, Shinichi*
IEEE Transactions on Dielectrics and Electrical Insulation, 14(3), p.572 - 576, 2007/06
Times Cited Count：5 Percentile：33.65(Engineering, Electrical & Electronic)Voltage holding capability of a 500 keV 22 A negative ion accelerator for JT-60U was experimentally examined. Voltage holding capability was strongly correlated with intensity of the light emitted inside the accelerator by applying the acceleration voltage. Namely, stable voltage holding was realized when the light emission was well suppressed. To examine the origin of the light emission, the correlation between the light intensity and the dark current was measured. The light intensity was linearly varied with the dark current. Further, it was indicated from the direction of the dark current that electrons were emitted from cathode grids by applying the acceleration voltage. In addition, the spectroscopy measurement of the light showed that the light had a broad peak at 420 nm. No particular spectra of hydrogen, oxygen and carbon have been observed. Therefore, the light emission seemed to be originated by electron excitation of FRP itself. From these results, it was thought that the voltage holding capability of the JT-60U negative ion accelerator could be improved by suppressing the electron emission from the cathode grids.
Kikuchi, Katsumi; Akino, Noboru; Hanada, Masaya; Ikeda, Yoshitaka; Kamada, Masaki; Kawai, Mikito; Mogaki, Kazuhiko; Noto, Katsuya; Usui, Katsutomi
JAEA-Technology 2007-027, 17 Pages, 2007/03
JAEA-Technology-2007-027.pdf:2.3MB
Voltage holding capability of the 500 kV accelerator in the JT-60 negative ion source that is one of the key issues for high performance of the JT-60 negative-ion-based NBI system was investigated. The achieved voltage holding capabilities with and without the beam acceleration were 400 kV and 455 kV, respectively. To understand a poor voltage holding capability of the negative ion source, correlation between the voltage holding capability and the light emitted inside the ion source was carefully examined. The acceleration voltage was stably applied at 400kV, where the light intensity was almost zero. Increasing the acceleration voltage beyond 400 kV, the voltage holding become very unstable where the light intensity increases in proportion to the acceleration voltage. The spectroscopy measurement showed that the light spectrum was a broad wavelength of 360 - 500 nm peaked at 420 nm. There was no line spectrum due to the gas discharge such as hydrogen, oxygen, carbon. From these results, it is seemed that the origin of the light emission is a cathode luminescence from the FRP (Fiberglass Reinforced Plastic) insulator in JT-60 negative ion source due to the electron impact. Moreover, breakdown phenomena at inside and outside of the ion source were examined by using photo-multipliers with fast data acquisition system. When the breakdown occurred inside the ion source, the breakdowns sequentially occurred at the spark gap switches outside of the ion source, which protect the FRP insulator from the flashover on its surface. Once the spark gap was turned on after the breakdown inside the ion source, the breakdowns at the spark gap occurred at lower voltage than the normal set value when the high voltage was applied again after 
70 ms interval. This result indicates that the voltage holding capability was limited by the spark gap switches in this operational sequence.
Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.
Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12
To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.
Kikuchi, Mitsuru; Matsuda, Shinzaburo; Yoshida, Naoaki*; Takase, Yuichi*; Miura, Yukitoshi; Fujita, Takaaki; Matsukawa, Makoto; Tamai, Hiroshi; Sakurai, Shinji; Ikeda, Yoshitaka; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 82(8), p.455 - 469, 2006/08
no abstracts in English
Ikeda, Yoshitaka; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Grisham, L. R.*; Hanada, Masaya; Honda, Atsushi; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; et al.
Nuclear Fusion, 46(6), p.S211 - S219, 2006/06
Times Cited Count：59 Percentile：87.2(Physics, Fluids & Plasmas)Recently, the extension of the pulse duration up to 30 sec has been intended to study quasi-steady state plasma on JT-60U N-NBI system. The most serious issue is to reduce the heat load on the grids for long pulse operation. Two modifications have been proposed to reduce the heat load. One is to suppress the beam spread which may be caused by beamlet-beamlet interaction in the multi-aperture grid due to the space charge force. Thin plates were attached on the extraction grid to modify the local electric field. The plate thickness was optimized to steer the beamlet deflection. The other is to reduce the stripping loss, where the electron of the negative ion beam is stripped and accelerated in the ion source and then collides with the grids. The ion source was modified to reduce the pressure in the accelerator column to suppress the beam-ion stripping loss. Up to now, long pulse injection of 17 sec for 1.6 MW and 25 sec for 1 MW has been obtained by one ion source with these modifications.
Kikuchi, Katsumi; Akino, Noboru; Ikeda, Yoshitaka; Usui, Katsutomi; Umeda, Naotaka; Oga, Tokumichi; Kawai, Mikito; Mogaki, Kazuhiko
JAEA-Technology 2006-016, 25 Pages, 2006/03
JAEA-Technology-2006-016.pdf:2.54MB
The 500 keV negative-ion based neutral beam injector (NBI) has been operated to heat plasma and drive plasma current on JT-60U since 1996. The ion source was designed to accelerate the negative ions up to 500 keV. During the last 10 years, the accelerated voltage of the negative ion beam has been limited to 400 keV by breakdowns in the accelerator. To understand the breakdown phenomena, the characteristics of the voltage holding of the ion source were studied without beam extraction. Outgassing with the main species of m/e=28 was observed when high voltage was applied even without breakdowns. It was noticed that the fraction of the main species at breakdown was almost the same as without breakdowns. Conditioning reduced the outgassing and resulted in improvement of the voltage holding capability. Inside the ion source, a brightening was observed even without breakdown. The brightening intensity was suppressed by increasing the D pressure in the accelerator in the range of 10
Pa to 0.5 Pa. Since the voltage holding was also improved with D pressure, breakdowns seemed to correlate with the brightening phenomena in the accelerator. This report gives the preliminary results of outgassing and brightening measurements when the high voltage was applied on the accelerator without beam extraction.
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
Times Cited Count：13 Percentile：41.76(Physics, Fluids & Plasmas)The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.
Tsuchiya, Katsuhiko; Akiba, Masato; Azechi, Hiroshi*; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; et al.
Fusion Engineering and Design, 81(8-14), p.1599 - 1605, 2006/02
Times Cited Count：1 Percentile：9.98(Nuclear Science & Technology)no abstracts in English
