Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 31

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

Overview of national centralized tokamak program; Mission, design and strategy to contribute ITER and DEMO

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.

Journal Articles

Design study of national centralized tokamak facility for the demonstration of steady state high-$$beta$$ 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

 Times Cited Count:15 Percentile:48.09(Physics, Fluids & Plasmas)

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.

Journal Articles

N-NBI heating and current drive in JT-60U towards steady-state tokamak

Ikeda, Yoshitaka; Oikawa, Toshihiro; Ide, Shunsuke

Purazuma, Kaku Yugo Gakkai-Shi, 81(10), p.773 - 778, 2005/10

In steady-state tokamak fusion reactors, an efficient external current drive and a large fraction of the bootstrap current are required for non-inductive operation at low circulating power. NBI is a powerful and reliable actuator for current drive and heating. A negative ion-based NBI (N-NBI) with a high beam energy more than 350 keV has been installed in the JT-60U tokamak in order to study the NBI current drive and heating in an ITER relevant regime. This paper presents recent progress of N-NBI experiments and its system in JT-60U towards steady-state operation for ITER and tokamak fusion reactors.

Journal Articles

Steady-state operation of high-beta/low aspect ratio tokamak reactor with bootstrap current

Sengoku, Seio

Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.940 - 943, 2004/11

Recent spherical tokamak (ST) experiments exhibit many advantageous results including plasma start-up without center solenoid, higher fraction of non-inductive current, formation of internal thermal-barrier as seen on conventional tokamak. In order to reflect these efforts on the design of so called "non-inductive steady-state (SS) operation scenario" and "current ramp-up scenario" of low-aspect reactor, fractions of bootstrap current and neutral-beam-driven current on VECTOR-OPT reactor are estimated. The operation with this SS scenario is shown to be feasible if the normalized beta, $$beta$$n, is raised to grater than 5 typical in ST.

Journal Articles

Advanced control scenario of high-performance steady-state operation for JT-60 superconducting tokamak

Tamai, Hiroshi; Kurita, Genichi; Matsukawa, Makoto; Urata, Kazuhiro*; Sakurai, Shinji; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Miura, Yushi; Kizu, Kaname; Kamada, Yutaka; et al.

Plasma Science and Technology, 6(3), p.2281 - 2285, 2004/06

 Times Cited Count:0 Percentile:0.02(Physics, Fluids & Plasmas)

High performance steady-state operation for JT-60SC are evaluated by the TOPICS analysis. $$beta$$$$_N$$$$sim$$5 and bootstrap current fraction $$sim$$86% is kept steady at I$$_p$$=1.5 MA, B$$_t$$=2 T by neutral beam power of 11 MW. The ERATO-J analysis shows that the external-kink mode with multiple toroidal mode numbers of n=1 and n=2 is stable at $$beta$$$$_N$$ $$leq$$5.5 at the average ratio of conducting wall radius to plasma minor radius of about 1.2 with the wall stabilisation effect. Resistive wall modes, induced by a close location of the wall to plasma, is expected to be suppressed by the active feedback stabilisation with a set of non-axisymmetric field coils behind the stabilising plates. Further optimisation for the high-$$beta$$$$_N$$ accessibility by the plasma shaping is performed with the TOSCA analysis. The plasma shaping factor defined as S=(I$$_p$$/aB$$_t$$)q$$_9$$$$_5$$ and strongly correlated to the plasma elongation and triangularity, is scanned from $$sim$$4 to $$sim$$6, which extends the availability of current and pressure profile control for the high performance plasma operation.

Journal Articles

A Review of internal transport barrier physics for steady-state operation of tokamaks

Connor, J. W.*; Fukuda, Takeshi*; Garbet, X.*; Gormezano, C.*; Mukhovatov, V.*; Wakatani, Masahiro*; ITB Database Group; ITPA Topical Group on Transport and Internal Barrier Physics*

Nuclear Fusion, 44(4), p.R1 - R49, 2004/04

 Times Cited Count:259 Percentile:76.74(Physics, Fluids & Plasmas)

This paper first reviews the present state of theoretical and experimental knowledge regarding the formation and characteristics of ITBs in tokamaks. Specifically, the current status of theoretical modeling of ITBs is presented; then, an international ITB database based on experimental information extracted from some nine tokamaks is described and used to draw some general conclusions concerning the necessary conditions for ITBs to appear, comparing these with the theoretical models. The experimental situation regarding the steady-state, or at least quasi-steady-state, operation of tokamaks is reviewed and finally the issues and prospects for achieving such operational modes in ITER are discussed.

Journal Articles

Recent results and modification program of JT-60 toward high integrated performance

Matsukawa, Makoto; JT-60 Team

IEEE Transactions on Plasma Science, 32(1), p.135 - 143, 2004/02

 Times Cited Count:1 Percentile:3.1(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Evaluation of susceptibility on crevice corrosion for ITER vacuum vessel

Nakahira, Masataka

JAERI-Tech 2003-083, 79 Pages, 2003/11

JAERI-Tech-2003-083.pdf:10.29MB

The ITER Vacuum Vessel has a double-walled structure and cooling water is filled in between inner and outer shells. It is planned to apply T-welded joints with partial penetration at the connection between outer shell and rib. The length and gap of non-penetrated part are controlled and limited to less than 5mm and 0.5mm respectively. Although it can be considered to be low susceptibility, crevice corrosion can possibly occur, because the water is stagnant in the crevice and impurities will condense. In this report, the corrosion-crevice repassivation potential, E$$_{R,CREV}$$, was experimentally measured under the several density of NaCl solution, and compared to the steady-state corrosion potential in the pertinent environment, to evaluate the susceptibility. Simulated conditions are normal operating condition with water temperature of 150$$^{circ}$$C, baking operation with water temperature of 200$$^{circ}$$C and impurity condense by cyclic wet and dry condition.

Journal Articles

Observation of high recycling steady H-mode edge and compatibility with improved core confinement mode on JFT-2M

Kamiya, Kensaku; Kimura, Haruyuki; Ogawa, Hiroaki; Kawashima, Hisato; Tsuzuki, Kazuhiro; Sato, Masayasu; Miura, Yukitoshi; JFT-2M Group

Nuclear Fusion, 43(10), p.1214 - 1219, 2003/10

no abstracts in English

Journal Articles

Observation of high recycling steady H-mode edge and compatibility with improved core confinement mode on JFT-2M

Kamiya, Kensaku; Kimura, Haruyuki; Ogawa, Hiroaki; Kawashima, Hisato; Tsuzuki, Kazuhiro; Sato, Masayasu; Miura, Yukitoshi; JFT-2M Group

Nuclear Fusion, 43(10), p.1214 - 1219, 2003/10

 Times Cited Count:34 Percentile:72.26(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Dynamics of plasma during the formation of a weak negative central magnetic shear configuration using counter neutral beam injection in the JFT-2M tokamak

Kamiya, Kensaku; Kimura, Haruyuki; Ogawa, Hiroaki; Kawashima, Hisato; Tsuzuki, Kazuhiro; Isei, Nobuaki; Sato, Masayasu; Shinohara, Koji

Purazuma, Kaku Yugo Gakkai-Shi, 78(12), p.1361 - 1367, 2002/12

no abstracts in English

Journal Articles

Modified quasi-steady-state method to evaluate the mean power profiles of nuclear excursions in fissile solution

Nakajima, Ken; Yamamoto, Toshihiro; Miyoshi, Yoshinori

Journal of Nuclear Science and Technology, 39(11), p.1162 - 1168, 2002/11

 Times Cited Count:6 Percentile:41.16(Nuclear Science & Technology)

A modified quasi-steady-state method has been developed to evaluate the mean power during a nuclear excursion in fissile solution. The original method used the critical equation based on the one-group theory to calculate the reactivity. However, the one-group approximation reduces the calculation accuracy and the geometrical buckling used in the critical equation is not applicable to complex geometries. Then, we have modified the method to use the feedback coefficients of reactivity. Although the modified method requires an external calculation to obtain the feedback coefficients, it is applicable to complex geometries and gives more accurate results than the one-group approximation. Moreover, a new method to calculate the boiling power has been developed. using the experimental data of a supercritical experiment facility, SILENE. Experimental analyses were conducted to validate the new method for supercritical xperiments using CRAC and TRACY. The results showed good agreements with the experiments.

Journal Articles

Noninductive current drive and steady-state operation in JT-60U

Ushigusa, Kenkichi; Ide, Shunsuke; Oikawa, Toshihiro; Suzuki, Takahiro; Kamada, Yutaka; Fujita, Takaaki; Ikeda, Yoshitaka; Naito, Osamu; Matsuoka, Mamoru*; Kondoh, Takashi; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.255 - 277, 2002/09

 Times Cited Count:6 Percentile:3.03(Nuclear Science & Technology)

Studies on non-inductive current drive and development of an integrated steady-state high performance operation in JT-60 are reviewed. Experiments on lower hybrid current drive in JT-60 haven shown a large non-inductive current up to 3.5MA, high current drive efficiency of 3.6x1019m-2A/W. Basic studies on LH waves in JT-60 have contributed to understand current drive physics. Significant progress in neutral beam current drive has been made in JT-60 by testing the performance of negative ion based NBI (N-NBI). The CD efficiency of ~1.5x1019m-2A /W, and N-NB driven current of ~1MA have been demonstrated in N-NBCD. Strongly localized driven current by electron cyclotron current drive was identified with a fundamental O-mode scheme. Efficiency of 0.5x1019m-2A/W and EC driven current of 0.2MA were achieved and suppression of neo-classical tearing mode was demonstrated. Based on these developments, two integrated steady-state operation scenarios were developed in JT-60, which are reversed magnetic shear (R/S) plasmas and high bp ELMy H-mode. In these operation regimes, discharges have been sustained near the steady-state current profile under full non-inductive current drive. High performance plasmas with a high nDotETio and at high normalized density were also produced under fully non-inductive condition in high bp ELMy H-mode and R/S mode.

JAEA Reports

Solution exploration of plasma initiation and current ramp-up scenario in A-SSTR

Polevoi, A. R.; Nishio, Satoshi; Ushigusa, Kenkichi

JAERI-Tech 2000-001, p.16 - 0, 2000/01

JAERI-Tech-2000-001.pdf:0.85MB

no abstracts in English

Journal Articles

Conceptual design of JT-60SU

Ushigusa, Kenkichi

Purazuma, Kaku Yugo Gakkai-Shi, 74(2), p.117 - 125, 1998/02

no abstracts in English

Journal Articles

Temperature control of plasma grid for continuous operation in cesium-seeded volume negative ion source

Fujiwara, Yukio; Miyamoto, Naoki*; Okumura, Yoshikazu

Review of Scientific Instruments, 69(2), p.1173 - 1175, 1998/02

 Times Cited Count:7 Percentile:53.75(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Vertical positional instability in JT-60SU

; Nagashima, Keisuke; Ushigusa, Kenkichi; Kikuchi, Mitsuru

Fusion Engineering and Design, 38(4), p.417 - 428, 1998/00

 Times Cited Count:3 Percentile:32.94(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Creep properties of 20% cold-worked Hastelloy XR

Kurata, Yuji; Nakajima, Hajime

Journal of Nuclear Materials, 228, p.176 - 183, 1996/00

 Times Cited Count:12 Percentile:71.65(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

COOLOD-N: A Copmupter code, for the analysis of steady-state thermal hydraulics in plate-type research reactor

Kaminaga, Masanori

RIST News, (21), p.42 - 47, 1996/00

no abstracts in English

JAEA Reports

Stability of toroidal Alfven eigenmode in JT-60 super upgrade

Ozeki, Takahisa; C.Z.Cheng*; Nagashima, Keisuke

JAERI-Research 95-065, 22 Pages, 1995/10

JAERI-Research-95-065.pdf:0.75MB

no abstracts in English

31 (Records 1-20 displayed on this page)