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Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.
JAEA-Research 2010-019, 194 Pages, 2010/08
JAEA-Research-2010-019-01.pdf:48.47MBJAEA-Research-2010-019-02.pdf:19.4MB
This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m
. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.
Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07
Times Cited Count：141 Percentile：97.57(Physics, Fluids & Plasmas)Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).
Iimura, Koichi; Ogawa, Mitsuhiro; Tomita, Kenji; Tobita, Masahiro
JAEA-Technology 2009-021, 71 Pages, 2009/05
JAEA-Technology-2009-021.pdf:4.34MB
The preparation of a fuel transient test using the JMTR is advanced to conduct its irradiation test from 2011 F.Y. after re-operation of the JMTR. The fuel behavior for high burn-up BWR's under power ramping condition will be evaluated in simulating the BWR environmental condition using the shroud irradiation facility (Oarai Shroud Facility No.1) and 
He power-control type BOCA (Boiling Water Capsule) irradiation facility, which is composed of the capsule control device, He power-control device and boiling water capsule. In order to change the fuel irradiation conditions so as to treat high burn-up fuels (from 50 GWD/t-UO
to 110 GWD/t-U), it is necessary to revaluate the dose for the safety evaluation at the test fuel failure. In this report, evaluations for equivalent dose rate of each device and exposure dose of handling operators when all fission products released in the coolant of the capsule control device and the BOCA at fuel failure in the fuel transient test are summarized.
Ogawa, Mitsuhiro; Iimura, Koichi; Tomita, Kenji; Tobita, Masahiro
JAEA-Technology 2009-017, 254 Pages, 2009/05
JAEA-Technology-2009-017.pdf:15.04MB
In JMTR, upgrade of irradiation facilities is advanced to re-operate from 2011 F.Y. In order to irradiate test fuels of high-burnup, external exposure reassessment by direct and skyshine gamma rays of the nuclear fuel handling facility at JMTR was performed. In evaluation method, radiation source of maximum use of the nuclear fuel was calculated by using ORIGEN2 code. Dose equivalent rate for supervised area boundary was calculated by modeling reactor building at using shielding calculation codes QAD-CGGP2 and G33-GP2. As a result of evaluation, it was confirmed that the effective dose equivalent during year was low enough at supervised area boundary of the JMTR site.
Tobita, Kenji; Nishio, Satoshi; Sato, Masayasu; Sakurai, Shinji; Hayashi, Takao; Shibama, Yusuke; Isono, Takaaki; Enoeda, Mikio; Nakamura, Hirofumi; Sato, Satoshi; et al.
Nuclear Fusion, 47(8), p.892 - 899, 2007/08
Times Cited Count：59 Percentile：86.43(Physics, Fluids & Plasmas)The concept for a compact DEMO reactor named "SlimCS" is presented. Distinctive features of the concept is low aspect ratio (
= 2.6) and use of a reduced-size center solenoid (CS) which has a function of plasma shaping rather than poloidal flux supply. The reduced-size CS enables us to introduce a thin toroidal field (TF) coil system which contributes to reducing the weight and construction cost of the reactor. SlimCS is as compact as advanced commercial reactor designs such as ARIES-RS and produces 1 GWe in spite of moderate requirements for plasma parameters. Merits of low-, i.e. vertical stability for high elongation and high beta limit are responsible for such reasonable physics requirements.
Tobita, Kenji; Nishio, Satoshi; Sato, Masayasu; Sakurai, Shinji; Hayashi, Takao; Shibama, Yusuke; Isono, Takaaki; Enoeda, Mikio; Nakamura, Hirofumi; Sato, Satoshi; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2006/10
no abstracts in English
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Sato, Masayasu; Isono, Takaaki; Sakurai, Shinji; Nakamura, Hirofumi; Sato, Satoshi; Suzuki, Satoshi; Ando, Masami; et al.
Fusion Engineering and Design, 81(8-14), p.1151 - 1158, 2006/02
Times Cited Count：124 Percentile：98.96(Nuclear Science & Technology)no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
Times Cited Count：7 Percentile：22.45(Physics, Fluids & Plasmas)no abstracts in English
Tobita, Koichi; Soga, Tomonori; Mitsugi, Takeshi
Saikuru Kiko Giho, (21,別冊), p.27 - 39, 2003/12
Concerning with JOYO MK-3 program for improvement of its irradiation ability, design and fabrication of the shielding subassembly have been performed. And as a result of the achievement high neutron flux in MK-3 core, lifetime extension of control rod and reflector was required to decrease the reactor operation cost and the quantity of radioactive wastage. Therefore, the sodium bonded control rod and the ferritic stainless steel reflector have been developed for long-life design. This report describes about JOYO core component developments in the view point of those designs.
Ueta, Shohei; Emori, Koichi; Tobita, Tsutomu*; Takahashi, Masashi*; Kuroha, Misao; Ishii, Taro*; Sawa, Kazuhiro
JAERI-Research 2003-025, 59 Pages, 2003/11
JAERI-Research-2003-025.pdf:2.53MB
In the safety design requirements for the High Temperature Engineering Test Reactor (HTTR) fuel, it is determined that "the as-fabricated failure fraction shall be less than 0.2%" and "the additional failure fraction shall be small through the full service period". Therefore the failure fraction should be quantitatively evaluated during the HTTR operation. In order to measure the primary coolant activity, primary coolant radioactivity signals the in safety protection system, the fuel failure detection (FFD) system and the primary coolant sampling system are provided in the HTTR. The fuel and fission product behavior was evaluated based on measured data in the rise-to-power tests (1) to (4). The measured fractional releases are constant at 2
10
up to 60% of the reactor power, and then increase to 710 at full power operation. The prediction shows good agreement with the measured value. These results showed that the release mechanism varied from recoil to diffusion of the generated fission gas from the contaminated uranium in the fuel compact matrix.
; Hasegawa, Akira*; ; Tobita, Koichi
JNC TY9400 2002-010, 45 Pages, 2002/03
JNC-TY9400-2002-010.pdf:2.43MB
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Soga, Tomonori; Tobita, Koichi; Mitsugi, Takeshi; Miyakawa, Shunichi
Saikuru Kiko Giho, (8), p.13 - 22, 2000/09
None
Arii, Yoshio; ; ; ; Ito, Hideaki; Tobita, Koichi;
Nihon Genshiryoku Gakkai-Shi, 38(7), p.577 - 584, 1996/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)None
Tsutagi, Koichi; Seki, Masayuki; Tobita, Noriyuki; Nagai, Shuichiro; ; ;
PNC TN8410 91-256, 64 Pages, 1991/05
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Tsutagi, Koichi; Seki, Masayuki; Tobita, Noriyuki; ; ;
PNC TN8410 91-174, 40 Pages, 1991/02
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Nagai, Shuichiro; ; Tobita, Noriyuki; Seki, Masayuki; Tsutagi, Koichi; ;
PNC TN8410 91-010, 49 Pages, 1991/01
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; Tobita, Noriyuki; Seki, Masayuki; Tsutagi, Koichi; ;
PNC TN8430 88-006, 73 Pages, 1988/09
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