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Nakamura, Hirofumi; Hayashi, Takumi; Kawamura, Yoshinori; Yamanishi, Toshihiko; Tobita, Kenji; DEMO Plant Design Team
Proceedings of 9th IAEA Technical Meeting on Fusion Power Plant Safety (CD-ROM), 7 Pages, 2009/07
Tobita, Kenji; Nishio, Satoshi; Tanigawa, Hiroyasu; Enoeda, Mikio; Isono, Takaaki; Nakamura, Hirofumi; Tsuru, Daigo; Suzuki, Satoshi; Hayashi, Takao; Tsuchiya, Kunihiko; et al.
Journal of Nuclear Materials, 386-388, p.888 - 892, 2009/04
Times Cited Count：25 Percentile：83.26(Materials Science, Multidisciplinary)SlimCS is the conceptual design of a compact fusion DEMO plant assuming technologies foreseeable in 2020s-2030s. Considering continuity of blanket technology from the Japanese proposal on ITER-TBM, the prime option of blanket is water-cooled solid breeder with Li
TiO
and Be (or Be
Ti). A reduced-activation ferritic-martensitic steel and pressurized water are chosen as the structural material and coolant, respectively. Toroidal coils produce the peak magnetic field above 16 T using the RHQT processed NbAl conductors. The structure and materials of the conducting shell and divertor are also presented.
Nishi, Masataka; Yamanishi, Toshihiko; Hayashi, Takumi; DEMO Plant Design Team
Fusion Engineering and Design, 81(1-7), p.745 - 751, 2006/02
Times Cited Count：31 Percentile：88.1(Nuclear Science & Technology)The fusion DEMO plant is under designing at JAERI as a fusion machine following ITER, and it is designed with long-term steady operation and tritium breeding blanket in which more tritium is produced than consumption. Therefore, proper tritium accountancy control concept should be discussed and developed for its safety and operation. From the viewpoint of regulation for the radioisotopes, at first, it will be suitable to divide facilities of the fusion DEMO plant into three accountancy control blocks, that is, (1) the contaminated waste management facility, (2) the long term tritium storage facility, and (3) the fuel processing plant. In each block, tritium amount of receipt and delivery should be carefully accounted. The fuel processing plant involves tritium production in the blanket, therefore proper accounting method for produced tritium should be established. Furthermore, dynamic accountancy is indispensable to the fuel processing plant to monitor tritium inventory distribution for safety and optimum system control in addition to the accountancy under regulation.
Nakamura, Hirofumi; Sakurai, Shinji; Suzuki, Satoshi; Hayashi, Takumi; Enoeda, Mikio; Tobita, Kenji; DEMO Plant Design Team
Fusion Engineering and Design, 81(8-14), p.1339 - 1345, 2006/02
Times Cited Count：51 Percentile：94.78(Nuclear Science & Technology)no abstracts in English
Inoue, Takashi; Hanada, Masaya; Kashiwagi, Mieko; Nishio, Satoshi; Sakamoto, Keishi; Sato, Masayasu; Taniguchi, Masaki; Tobita, Kenji; Watanabe, Kazuhiro; DEMO Plant Design Team
Fusion Engineering and Design, 81(8-14), p.1291 - 1297, 2006/02
Times Cited Count：11 Percentile：60.27(Nuclear Science & Technology)Requirement and technical issues of the neutral beam inejctor (NBI) is discussed for fusion DEMO plant. The NBI for the fusion DEMO plant should be high efficiency, high energy and high reliability with long life. From the view point of high efficiency, use of conventional electrostatic accelerator is realistic. Due to operation under radiation environment, vacuum insulation is essential in the accelerator. According to the insulation design guideline, it was clarified that the beam energy of 1.5
2 MeV is possible in the accelerator. Development of filamentless, and cesium free ion source is required, based on the existing high current/high current density negative ion production technology. The gas neutralization is not applicable due to its low efficiency (60%). R&D on an advanced neutralization scheme such as plasma neutralization (efficiency: 
80%) is required. Recently, development of cw high power semiconductor laser is in progress. The paper shows a conceptual design of a high efficiency laser neutralizer utilizing the new semiconductor laser array.
Hayashi, Takao; Tobita, Kenji; Nishio, Satoshi; Ikeda, Kazuki*; Nakamori, Yuko*; Orimo, Shinichi*; DEMO Plant Design Team
Fusion Engineering and Design, 81(8-14), p.1285 - 1290, 2006/02
Times Cited Count：21 Percentile：78.83(Nuclear Science & Technology)Neutron transport calculations were carried out to evaluate the capability of metal hydrides and borohydrides as an advanced shielding material. Some hydrides indicated considerably higher hydrogen content than polyethylene and solid hydrogen. The hydrogen-rich hydrides show superior neutron shielding capability to the conventional materials. From the temperature dependence of dissociation pressure, ZrH and TiH can be used without releasing hydrogen at the temperature of less than 640 
C at 1 atm. ZrH and Mg(BH
) can reduce the thickness of the shield by 30% and 20% compared to a combination of steel and water, respectively. Mixing some hydrides with F82H produces considerable effects in 
-ray shielding. The neutron and -ray shielding capabilities decrease in order of ZrH Mg(BH) and F82H TiH and F82H water and F82H.
Sato, Masayasu; Sakurai, Shinji; Nishio, Satoshi; Tobita, Kenji; Inoue, Takashi; Nakamura, Yukiharu; Shinya, Kichiro*; Fujieda, Hirobumi*; DEMO Plant Design Team
Fusion Engineering and Design, 81(8-14), p.1277 - 1284, 2006/02
Times Cited Count：14 Percentile：68.12(Nuclear Science & Technology)no abstracts in English
Nishio, Satoshi; Omori, Junji*; Kuroda, Toshimasa*; Tobita, Kenji; Enoeda, Mikio; Tsuru, Daigo; Hirose, Takanori; Sato, Satoshi; Kawamura, Yoshinori; Nakamura, Hirofumi; et al.
Fusion Engineering and Design, 81(8-14), p.1271 - 1276, 2006/02
Times Cited Count：20 Percentile：78.83(Nuclear Science & Technology)The design guideline for the blanket is decided to meet the mission of the DEMO plant which is expected to use technologies to be proven by 2020 and present an economical prospect of fusion energy in the operational time of the reactor. To moderate the technological extrapolation, the structural material of reduced activation ferritic steel (F82H), ceramic tritium breeder of LiTiO and neutron multiplier of Be are introduced. To improve the economical aspect, the coolant material of the supercritical water with inlet/outlet temperatures of 280/510C, coolant pressure of 25 MPa is chosen. Resultantly the thermal efficiency of 41% is achieved. To obtain higher plasma performance, MHD instabilities suppressing shell structure is adopted with structural compatibility to the blanket structure. To meet higher plant availability requirement (more than 75%), the hot cell maintenance approach is selected for the replaceable power core components.
Konishi, Satoshi; Nishio, Satoshi; Tobita, Kenji; DEMO Design Team
Fusion Engineering and Design, 63-64, p.11 - 17, 2002/12
Times Cited Count：50 Percentile：93.5(Nuclear Science & Technology)The first fusion power plant DEMO must have some reality that ITER and other facilities in the same period are expected to prove its feasibility. The DEMO should also be so attractive and advanced that the future society would be interested in constructing based on its concept. The present DEMO plant concept intends to satisfy these antagonistic requirements assuming construction in 2030s immediately after successful completion of fundamental ITER mission. A steady tokamak is minimized to have 5.8m of major radius with 2.3GW with Q exceeds 30. Modestly ambitious plasma parameters are chosen. Technology improvement is assumed to make maximum 20 T magnet, metal first wall and super critical water cooled ITER-like blanket modules feasible. Tritium inventory is reduced to 1kg with improved safety system concept. This conceptual design identifies various technical issues that are expected to be solved by intensive R&D efforts during ITER period, and indicates a possible step immediately after ITER.
Hiwatari, Ryoji; Watanabe, Kazuhito; Aoki, Akira; Tobita, Kenji; Demo Design Joint Special Team
no journal, ,
The conceptual design activity for a fusion Demo plant by the DEMO design joint special team has been started according to the report by the Joint-Core Team for the establishment of technology based required for the development of a Fusion DEMO reactor. One of the main subjects will be the operation plan for DEMO in the intermediate check and review around 2020. In this presentation, the present result on the operation plan for DEMO is reported. Three categories are considered; (1) Operation plan for demonstration of electric generation, (2) Operation plan for demonstration of feasibility of fusion energy, (3) Data acquisition plan. From those view points, experimental subjects, technical skill and acquisition data are listed up as for core plasma, in-vessel components (blanket and divertor), fuel cycle system, plant operation, remote maintenance and inspection, safety system, environmental effect. A preliminary operation plan for DEMO based on the Monju operation plan will be reported.
