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Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.
Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11
In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250
C in a vacuum of 10 
Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.
Ogawa, Hiroaki; Kitazawa, Sin-iti; Sugie, Tatsuo; Katsunuma, Atsushi*; Kitazawa, Daisuke*; Omori, Keisuke*; Itami, Kiyoshi
no journal, ,
no abstracts in English
Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.
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no abstracts in English
Kamiya, Kensaku; Honda, Mitsuru; Urano, Hajime; Yoshida, Maiko; Kamada, Yutaka
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In this study, we perform to identify the boundary condition for the toroidal plasma flow, which is known to play an important role for an improved plasma stability and/or confinement, to improve the prediction in the plasma core region by a code, experimentally. Boundary condition of toroidal plasma flow imposed at the separatrix in JT-60U ELMy H-mode plasmas has been identified, comparing between co- and counter-NBI discharges. Toroidal plasma flow at the separatrix can become non-zero value, varying with momentum input direction, but being unaffected by the ELM event. The results indicate that the viscosity damping due to SOL flow through ion-neutral collision may not affect strongly ion parallel momentum transfer.
Nakano, Tomohide; Shumack, A.*; Maggi, C. F.*; Reinke, M.*; Lawson, K.*; P
tterich, T.*; Brezinsek, S.*; Lipschultz, B.*; Matthews, G. F.*; Chernyshova, M.*; et al.
no journal, ,
In an European tokamak device, JET, an existing high-resolution X-ray crystal spectrometer was upgraded together with installation of the W divertor for the purpose of monitoring the W density in the core plasma. We have identified W
, W
and Mo
lines by comparing the spectrum observed by this spectrometer and that calculated by an atomic structure code. Further, from the intensities of these spectral lines, the W density and the Mo density over an electron density were determined to be 
and 
, respectively. The determined W density was in good agreement with that from another spectrometer. In addition, the plasma effective charge evaluated from the continuum intensity observed by the X-ray spectrometer was in agreement with that from a visible spectrometer within a factor of three. From these agreements, it is probable that the determined W and Mo density are valid. In contrast, the determined W density is only 15% compared with that from an soft X-ray array measurement. This inconsistency will be investigated in the near future.
Shiraishi, Junya; Miyato, Naoaki; Matsunaga, Go
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no abstracts in English
Hayashi, Nobuhiko; Jeronimo, G.*; Honda, Mitsuru; Shimizu, Katsuhiro; Hoshino, Kazuo; Ide, Shunsuke; Gerardo, G.*; Sakamoto, Yoshiteru; Suzuki, Takahiro; Urano, Hajime
no journal, ,
no abstracts in English
Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Yoshida, Maiko; Hayashi, Nobuhiko; Kamiya, Kensaku; Matsuyama, Akinobu; Shinohara, Koji; Matsunaga, Go; Nakata, Motoki; et al.
no journal, ,
no abstracts in English
Yamamoto, Tsuyoshi; Hatae, Takaki; Yatsuka, Eiichi; Sugie, Tatsuo; Ogawa, Hiroaki; Takeuchi, Masaki; Kitazawa, Sin-iti; Ota, Kazuya*; Hashimoto, Yasunori*; Nakamura, Kitaru*; et al.
no journal, ,
no abstracts in English
Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Umeda, Naotaka; Hiratsuka, Junichi; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; et al.
no journal, ,
One of the key issues for producing high current beams in JT-60SA is a uniform production of the negative ions over the large ion extraction area. Non-uniformity of the negative ion beams in the JT-60 negative ion source was improved by modifying the magnetic filter in the source from the PG filter to a tent-shaped filter. In this work, in order to clarify the influence of the magnetic filter modification on arc efficiency and co-electron current is investigated by means of measurements of H ion, H atoms, co-electron current and beam intensity. As a result, the arc efficiency increase due to increase of H ions and H atoms by reduction of filter field. Although the higher electrons current was extracted than the original PG filter, the co-extracted electron could be suppressed by optimization of the bias voltage. This result contributes to extend the pulse duration time up to 100 s for JT-60SA.
Miyata, Yoshiaki; Suzuki, Takahiro; Ide, Shunsuke; Urano, Hajime; Takechi, Manabu
no journal, ,
It is essential for a stable plasma equilibrium control to reconstruct an accurate plasma boundary in tokamak devices. Cauchy Condition Surface (CCS) method is a numerical approach to calculate the spatial distribution of the magnetic flux outside a hypothetical plasma surface and reconstruct the plasma boundary from the magnetic measurements located outside the plasma. It is found that the optimum number of unknown parameters and shape of the CCS for minimizing errors in the reconstructed plasma shape increase in proportion to the plasma size. It is shown that the accuracy of the plasma shape reconstruction greatly improves by using the optimum number of unknown parameters. The assessment of accuracy of plasma shape reconstruction by CCS method in JT-60SA is reported.
Nakamura, Shigetoshi; Shibama, Yusuke; Masaki, Kei; Sakasai, Akira
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no abstracts in English
Shimizu, Katsuhiro; Hoshino, Kazuo; Kawashima, Hisato; Takizuka, Tomonori*
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no abstracts in English
Tsuru, Daigo; Sakurai, Shinji; Nakamura, Shigetoshi; Ozaki, Hidetsugu; Seki, Yohji; Yokoyama, Kenji; Suzuki, Satoshi
no journal, ,
no abstracts in English
Shimada, Takahiko; Ishikawa, Masao; Yatsuka, Eiichi; Hatae, Takaki; Itami, Kiyoshi
no journal, ,
Neutronic analysis has been carried out for the detailed design of Edge Thomson Scattering System (ETS) which is procured by JAEA in the ITER project. ETS measures the profile of electron temperature and density in the edge region of the plasma and consists of the laser injection system and the optical collection system installed in the EQ port plug. The optical collection system consists of many mirrors. High nuclear heating of mirrors could distorts them and deteriorates measurement accuracy. In order to reduce nuclear heating of optical mirrors, the effect of materials on nuclear heating of the optical mirrors has been evaluated. As a result, nuclear heating rate can be reduced about 25% by replacing the material of the first mirror (plasma facing mirror) from molybdenum to SUS316. Also it was found that nuclear heating rate of other mirrors can decrease about 65% by replacing materials from SUS316 to Aluminium. As described above, the appropriate material for each optical mirrors can be selected by nutronic analysis.
Moriyama, Shinichi; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Hinata, Jun; Sato, Yoshikatsu; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
no abstracts in English
Kobayashi, Takayuki; Moriyama, Shinichi; Isayama, Akihiko; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; et al.
no journal, ,
A high-power long-pulse dual-frequency gyrotron, which can be operated at both 110 GHz and 138 GHz independently, was successfully developed for electron cyclotron heating and current drive in JT-60SA. The output power of 1 MW and the pulse length of 100 s were obtained at both frequencies with the high oscillation efficiency (not including an efficiency enhancement by collector potential depression) of 34% (110 GHz) and 32% (138 GHz), respectively, for the first time. The target of the JT-60SA gyrotron was fully satisfied by this gyrotron. An optimization of the electron pitch factor was a key to obtain the high efficiencies, and oscillation characteristics of the gyrotron were experimentally confirmed.
Nakaniwa, Koichi; Tanaka, Hiroshi; Ito, Yuzuru; Wakai, Eiichi; Yokomine, Takehiko*
no journal, ,
In the validation test of the lithium (Li) target system facility under the International Fusion Materials Irradiation Facility/Engineering Validation and Engineering Design Activities (IFMIF/EVEDA), the evaluation test of the flow stability is performed using the 1/2.6 scale in the flow channel of the width of the Li target in the EVEDA Li Test Loop. In this study, to proceed the integrity assessment of the equipment based on the expertise obtained in the validation test of the EVEDA Li test loop, a small water experiment device which is the simulation of the target part, the downstream pipe and the quench tank arranged downstream thereof, or the modification of the flow channel of the downstream pipe, was fabricated. Along with the observation of the high-speed liquid flow by visualization experiments, to confirm the generation conditions of cavitation, an accelerometer was installed in the pipes, and flow properties evaluation was performed with the flow rate, vacuum and temperature as variables. In the observation results, the flow stability in the target up to the speed of 15m/s was confirmed and the spread of the flow in the downstream pipe with the increase in the velocity, was observed. Also, in the evaluation by an accelerometer, at the speed of 8m/s, under the pressure conditions from 20kPa to the atmospheric pressure, the noise values in the downstream pipes are small and the values hardly changed. On the other hand, the noise values were confirmed to increase as the flow velocity increases to 12m/s, 15m/s and vacuum. From now on, the intermittency of the noise phenomena will be examined in detail, and analysis of the flow stability and the optimization of the downstream pipe structure will be examined.
Urano, Hajime
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The effects of hydrogen isotope in JT-60U H-mode plasmas are reported in this presentation.
Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Itami, Kiyoshi; Suito, Satoshi*; Araki, Takashi*; Iwamoto, Kohei*; Takeda, Yuya*
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