Dismantlement of large fusion experimental device JT-60U

Ikeda, Yoshitaka; Okano, Fuminori; Sakasai, Akira; Hanada, Masaya; Akino, Noboru; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; Kubo, Hirotaka; Kobayashi, Kazuhiro; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(4), p.167 - 178, 2014/12

https://doi.org/10.3327/taesj.J14.007

The JT-60U torus was disassembled so as to newly install the superconducting tokamak JT-60SA torus. The JT-60U used the deuterium for 18 years, so the disassembly project of the JT-60U was the first disassembly experience of a fusion device with radioactivation in Japan. All disassembly components were stored with recording the data such as dose rate, weight and kind of material, so as to apply the clearance level regulation in future. The lessons learned from the disassembly project indicated that the cutting technologies and storage management of disassembly components were the key factors to conduct the disassembly project in an efficient way. After completing the disassembly project, efforts have been made to analyze the data for characterizing disassembly activities, so as to contribute the estimation of manpower needs and the radioactivation of the disassembly components on other fusion devices.

Core confirmation test in system startup test of the fast breeder reactor MONJU

Jo, Takahisa; Goto, Takehiro; Yabuki, Kentaro; Ikegami, Kazunori; Miyagawa, Takayuki; Mori, Tetsuya; Kubo, Atsuhiko; Kitano, Akihiro; Nakagawa, Hiroki; Kawamura, Yoshiaki; et al.

JAEA-Technology 2010-052, 84 Pages, 2011/03

JAEA-Technology-2010-052.pdf:17.14MB

The prototype fast breeder reactor MONJU resumed the System Startup Test (SST) on May 6th 2010 after five months and fourteen years shutdown since the sodium leakage of the secondary heat transport system on December 1995. Core Confirmation Test (CCT) is the first step of SST, which consists of three steps. CCT was finished on July 22nd after 78 days tests. CCT is composed 20 test items including control rods' worth evaluation, radiation dose measurement etc..

Overview of the national centralized tokamak programme

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

https://doi.org/10.1088/0029-5515/46/3/S05

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.

Design study of national centralized tokamak facility for the demonstration of steady state high- plasma operation

Tamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.

Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12

https://doi.org/10.1088/0029-5515/45/12/023

Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.

Diagnostics system of JT-60U

Sugie, Tatsuo; Hatae, Takaki; Koide, Yoshihiko; Fujita, Takaaki; Kusama, Yoshinori; Nishitani, Takeo; Isayama, Akihiko; Sato, Masayasu; Shinohara, Koji; Asakura, Nobuyuki; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.482 - 511, 2002/09

https://doi.org/10.13182/FST02-A242

The diagnostic system of JT-60U (JT-60upgrade) is composed of about 50 individual diagnostic devices. Recently, the detailed radial profile measurements of plasma parameters have been improved, so that the internal structure of plasmas has been explored. The understanding of plasma confinement has been enhanced by density and temperature fluctuation measurements using a mm-wave reflectometer and electron cyclotron emission measurements respectively. In addition, the real-time control experiments of electron density, neutron yield, radiated power and electron temperature gradient have been carried out successfully by corresponding diagnostic devices. These measurements and the real time control contribute to improving plasma performance. Diagnostic devices for next generation fusion devices such as a CO2 laser interferometer/polarimeter and a CO2 laser collective Thomson scattering system have been developed.

Evaluation of thermal striping for the plugging system in the secondary auxiliary cooling system in JOYO

Isozaki, Kazunori; Ogawa, Toru; Kubo, Atsuhiko; Sugaya, Kazushi*; Aoki, Hiroshi; Ozawa, Kenji

PNC TN9410 98-055, 92 Pages, 1998/05

PNC-TN9410-98-055.pdf:6.0MB

Scrutiny based on the convenient evaluation to verify whether we have the place where thermal striping in the pipe confluence part was thought to be a primary factor for the heavy accident or not has been done in JOYO. As the result, the big temperature difference (Tin) of the simple inner pipe confluence part existed at the inner pipe confluence part of the plugging system in the secondary main and auxiliary cooling system. Therefore, detailed evaluation of thermal striping was needed. With the thermocouples of high response installed, the temperature fluctuation in outer surface of the pipe was measured on the secondary auxiliary plugging system for the reason why the temperature difference (Tin) was the biggest. And, the temperature fluctuation in inner surface of the pipe and stress occurring in the pipe plate thickness direction was evaluated by means of the temperature fluctuation measurement result and non-linear structure analysis system "FINAS". The above-mentioned evaluation results were as follows. (1)The maximum temperature fluctuation occurring in the pipe was always located from the center of inner pipe confluence to 10mm position of the down-stream side. (2)The maximum temperature fluctuation range was about 33C in outer surface of the pipe. And, controlling frequency of the temperature fluctuation was 0.04Hz and 0.09Hz. (3)Time delay was almost never contained in the temperature fluctuation elements between inner and outer surface of the pipe by dint of analysis results of the heat conduction by "FINAS". And, the big temperature distribution did not occur in the pipe plate thickness direction was confirmed that the big temperature distribution did not occur in the pipe plate thickness direction. (4)The temperature fluctuation in the pipe inner surface and the stress occurring in the pipe plate thickness direction was evaluated by use of result of the temperature fluctuation measurement and the heat conduction ...

Optimization of diagnostics allocation on JT-60 super advanced

Koide, Yoshihiko; Kubo, Hirotaka; Sakurai, Shinji; Sukegawa, Atsuhiko; Matsukawa, Makoto; Kamada, Yutaka; JT-60SA Design Team

no journal, , 

no abstracts in English