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Journal Articles

Research and development status on fusion DEMO reactor design under the Broader Approach

Tobita, Kenji; Federici, G.*; Okano, Kunihiko

Fusion Engineering and Design, 89(9-10), p.1870 - 1874, 2014/10

 Times Cited Count:19 Percentile:9.49(Nuclear Science & Technology)

The goal of the DEMO reactor design under the Broader Approach (BA) is to develop possible pre-conceptual designs of DEMO by addressing key design issues and options in physics, technology and system engineering for DEMO. The joint work between EU and Japan for the DEMO design started with a benchmark of systems codes. Cross-checking between the EU systems code PROCESS and the JA systems code TPC showed a good agreement for relatively conservative plasma parameters. In parallel, critical design issues on DEMO have been studied. In order to resolve the problem on divertor heat removal, a reduction of divertor heat load due to plasma detachment and advanced divertor concepts such as super-X and snowflake configuration has been investigated. Regarding remote maintenance (RM), various RM concepts based on different sector segmentations and access ports has been studied to allow reasonable plant availability under severe in-vessel dose rate.

Journal Articles

Study of safety features and accident scenarios in a fusion DEMO reactor

Nakamura, Makoto; Tobita, Kenji; Gulden, W.*; Watanabe, Kazuhito*; Someya, Yoji; Tanigawa, Hisashi; Sakamoto, Yoshiteru; Araki, Takao*; Matsumiya, Hisato*; Ishii, Kyoko*; et al.

Fusion Engineering and Design, 89(9-10), p.2028 - 2032, 2014/10

 Times Cited Count:10 Percentile:26.44(Nuclear Science & Technology)

After the Fukushima Dai-ichi nuclear accident, a social need for assuring safety of fusion energy has grown gradually in the Japanese (JA) fusion research community. DEMO safety research has been launched as a part of BA DEMO Design Activities (BA-DDA). This paper reports progress in the fusion DEMO safety research conducted under BA-DDA. Safety requirements and evaluation guidelines have been, first of all, established based on those established in the Japanese ITER site invitation activities. The amounts of radioactive source terms and energies that can mobilize such source terms have been assessed for a reference DEMO, in which the blanket technology is based on the Japanese fusion technology R&D programme. Reference event sequences expected in DEMO have been analyzed based on the master logic diagram and functional FMEA techniques. Accident initiators of particular importance in DEMO have been selected based on the event sequence analysis.

Journal Articles

Key aspects of the safety study of a water-cooled fusion DEMO reactor

Nakamura, Makoto; Tobita, Kenji; Someya, Yoji; Tanigawa, Hisashi; Gulden, W.*; Sakamoto, Yoshiteru; Araki, Takao*; Watanabe, Kazuhito*; Matsumiya, Hisato*; Ishii, Kyoko*; et al.

Plasma and Fusion Research (Internet), 9, p.1405139_1 - 1405139_11, 2014/10

Key aspects of the safety study of a water-cooled fusion DEMO reactor is reported. Safety requirements, dose target, DEMO plant model and confinement strategy of the safety study are briefly introduced. The internal hazard of a water-cooled DEMO, i.e. radioactive inventories, stored energies that can mobilize these inventories and accident initiators and scenarios, are evaluated. It is pointed out that the enthalpy in the first wall/blanket cooling loops, the decay heat and the energy potentially released by the Be-steam chemical reaction are of special concern for the water-cooled DEMO. An ex-vessel loss-of-coolant of the first wall/blanket cooling loop is also quantitatively analyzed. The integrity of the building against the ex-VV LOCA is discussed.

Journal Articles

Development of a methodology to evaluate characteristics of energy technology by conjoint analysis

Hiwatari, Ryoji*; Okano, Kunihiko*; Asaoka, Yoshiyuki*; Nagano, Koji*; Ogawa, Yuichi*; Kato, Takaaki*; Tobita, Kenji; Norimatsu, Takayoshi*

Denryoku Chuo Kenkyusho Hokoku (L07012), P. 34, 2008/07

Key to take public acceptance into account on the energy system is how to evaluate and compare quantitatively the merits and the demerits of each energy system from the public viewpoint. For this purpose, a method to evaluate the property of energy technology is developed based on the conjoint analysis technique. Based on the statistical method, utility values for energy abundance, environmental load (i.e. CO$$_{2}$$ emission), stability of supply, sense of security, and other features as well as economic performance, are estimated from several thousands of choice experiments to more than 1600 respondents volunteered in the study. The basic methodology developed in this study establishes the first step to assess energy technology quantitatively on a common standard, and needs further integration with other factors, such as waste generation other than CO$$_{2}$$ emission.

Journal Articles

Research and development of nuclear fusion

Ushigusa, Kenkichi; Seki, Masahiro; Ninomiya, Hiromasa; Norimatsu, Takayoshi*; Kamada, Yutaka; Mori, Masahiro; Okuno, Kiyoshi; Shibanuma, Kiyoshi; Inoue, Takashi; Sakamoto, Keishi; et al.

Genshiryoku Handobukku, p.906 - 1029, 2007/11

no abstracts in English

Journal Articles

Introduction to plasma fusion energy

Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.

Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03

no abstracts in English

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

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

 Times Cited Count:13 Percentile:54.2(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.

Journal Articles

Engineering design and control scenario for steady-state high-beta operation in national centralized tokamak

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:89.15(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Intelligible seminar on fusion reactors, 12; Next step toward the realization of fusion reactors, Future vision of fusion energy research and development

Okano, Kunihiko*; Kurihara, Kenichi; Tobita, Kenji

Nippon Genshiryoku Gakkai-Shi, 48(1), p.48 - 56, 2006/01

no abstracts in English

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:50.65(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

Path toward commercial fusion power plants

Okano, Kunihiko*; Kikuchi, Mitsuru; Tobita, Kenji; Hiwatari, Ryoji*

Purazuma, Kaku Yugo Gakkai-Shi, 81(11), p.839 - 848, 2005/11

no abstracts in English

Journal Articles

Experimental validation of beam particle self interaction in JT-60U by use of N-NB

Okano, Kunihiko*; Suzuki, Takahiro; Umeda, Naotaka; Hiwatari, Ryoji*; Masaki, Kei; Tobita, Kenji; Fujita, Takaaki

Purazuma, Kaku Yugo Gakkai-Shi, 81(8), p.579 - 580, 2005/08

In a toroidal system, circulating fast ions generated by neutral beam injection affect the beam stopping cross-section of the neutral beam itself. This effect is called "beam particle self-interaction (BPSI)". In a recent experiment in JT-60U with 350 keV H$$^{0}$$ beam, an indication of this BPSI effect has been found for the first time. In a low density discharge at about 1$$times$$10$$^{19}$$m$$^{-3}$$, the beam shine-through decreased by about 35% within several hundred msec after beam injection. This result is consistent with a prediction by the BPSI theory.

Journal Articles

Progress in physics and technology developments for the modification of JT-60

Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Hayashi, Nobuhiko; Urata, Kazuhiro*; Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Kudo, Yusuke; et al.

Plasma Science and Technology, 6(1), p.2141 - 2150, 2004/02

 Times Cited Count:2 Percentile:92.83(Physics, Fluids & Plasmas)

The dominant issue for the the modification program of JT-60 (JT-60SC) is to demonstrate the steady state reactor relevant plasma operation. Physics design on plasma parameters, operation scenarios, and the plasma control method are investigated for the achievement of high-$$beta$$. Engineering design and the R&D on the superconducting magnet coils, radiation shield, and vacuum vessel are performed. Recent progress in such physics and technology developments is presented.

Journal Articles

Design and technology development of solid breeder blanket cooled by supercritical water in Japan

Enoeda, Mikio; Kosaku, Yasuo; Hatano, Toshihisa; Kuroda, Toshimasa*; Miki, Nobuharu*; Homma, Takashi; Akiba, Masato; Konishi, Satoshi; Nakamura, Hirofumi; Kawamura, Yoshinori; et al.

Nuclear Fusion, 43(12), p.1837 - 1844, 2003/12

 Times Cited Count:92 Percentile:5.89(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Socio-economic study of fusion energy at the Japan Atomic Energy Research Institute

Konishi, Satoshi; Okano, Kunihiko*; Tokimatsu, Koji*; Ito, Keishiro*; Ogawa, Yuichi*

Fusion Engineering and Design, 69(1-4), p.523 - 529, 2003/09

 Times Cited Count:4 Percentile:66.65(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Objectives and design of the JT-60 superconducting tokamak

Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.

Nuclear Fusion, 43(7), p.606 - 613, 2003/07

no abstracts in English

Journal Articles

Objectives and design of the JT-60 superconducting tokamak

Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Cho, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.

Nuclear Fusion, 43(7), p.606 - 613, 2003/07

 Times Cited Count:33 Percentile:27.31(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Potential of fusion energy in the context of tritium supply

Tokimatsu, Koji*; Asaoka, Yoshiyuki*; Okano, Kunihiko*; Konishi, Satoshi

Fusion Science and Technology, 41(3), p.831 - 834, 2002/05

no abstracts in English

JAEA Reports

Conceptual design of solid breeder blanket system cooled by supercritical water

Enoeda, Mikio; Ohara, Yoshihiro; Akiba, Masato; Sato, Satoshi; Hatano, Toshihisa; Kosaku, Yasuo; Kuroda, Toshimasa*; Kikuchi, Shigeto*; Yanagi, Yoshihiko*; Konishi, Satoshi; et al.

JAERI-Tech 2001-078, 120 Pages, 2001/12

JAERI-Tech-2001-078.pdf:8.3MB

This report is a summary of the design works, which was discussed in the design workshop held in 2000 for the demonstration (DEMO) blanket aimed to strengthen the commercial competitiveness and technical feasibility simultaneously. The DEMO blanket must supply the feasibility and experience of the total design of the power plant and the materials. This conceptual design study was performed to determine the updated strategy and goal of the R&D of the DEMO blanket which applies the supercritical water cooling proposed in A-SSTR, taking into account the recent progress of the plasma research and reactor engineering technology.

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