Application of Cherenkov light observation to reactor measurements, 3; Evaluation of spent fuel elements of LWRs with Cherenkov light estimation system

Yamamoto, Keiichi; Takeuchi, Tomoaki; Hayashi, Takayasu*; Kosuge, Fumiaki*; Tsuchiya, Kunihiko

JAEA-Testing 2016-002, 25 Pages, 2016/11

JAEA-Testing-2016-002.pdf:4.97MB

Development of the reactor measurement system has been carried out to obtain the real-time in-core nuclear and thermal information, where the quantitative measurement of brightness of Cherenkov light was investigated. The system would be applied as a monitoring system in severe accidents and for the advanced operation management technology in existing LWRs. This report summarized the modification of Cherenkov light estimation system described JAEA-Testing 2015-001 and the result of the burn-up evaluation by Cherenkov light image emitted from spent fuel elements of LWRs with the modified system.

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

https://doi.org/10.1016/j.fusengdes.2014.04.062

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.

Conceptual design of the SlimCS fusion DEMO reactor

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:48.47MB
JAEA-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.

Crystal structure of advanced lithium titanate with lithium oxide additives

Hoshino, Tsuyoshi; Sasaki, Kazuya*; Tsuchiya, Kunihiko; Hayashi, Kimio; Suzuki, Akihiro*; Hashimoto, Takuya*; Terai, Takayuki*

Journal of Nuclear Materials, 386-388, p.1098 - 1101, 2009/04

https://doi.org/10.1016/j.jnucmat.2008.12.289

no abstracts in English

Torus configuration and materials selection on a fusion DEMO reactor, SlimCS

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

https://doi.org/10.1016/j.jnucmat.2008.12.197

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 LiTiO and Be (or BeTi). 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.

Detaching test on an irradiated mock-up contaminated with tritium from the core of JMTR

Tomita, Kenji; Tsuchiya, Kunihiko; Onuma, Yuichi; Inoue, Shuichi; Watanabe, Hiroyuki; Saito, Takashi; Kikuchi, Taiji; Hayashi, Kimio; Kitajima, Toshio

JAEA-Technology 2008-036, 61 Pages, 2008/06

JAEA-Technology-2008-036.pdf:7.47MB

The second in-situ irradiation experiment using a mock-up (ORIENT-II, JMTR capsule Number: 99M-54J) with a tritium breeder (LiTiO) pebble bed in the Japan Materials Testing Reactor (JMTR) was finished on Aug. 1, 2006. Consideration on the detaching procedure of the irradiated mock-up contaminated with tritium with pebble bed and a detaching test of this mock-up was carried out. The tritium removal properties were examined in the irradiated mock-up, the sweep gas tube, the protective tube and the junction box, for the decreasing of the tritium release to the area of detaching test. Melting/enclosed tests of sealing plug were also carried out for the prevention of tritium leakage from sweep gas lines of pebble bed. Then, the detaching test of the pebble bed was carried out. This report describes the results of tritium removal tests, examination of the detaching procedure, and the detaching test, as well as knowledge obtained from these tests and works.

Calculated positions of point nodes in the gap structure of the borocarbide superconductor YNiBC

Nagai, Yuki*; Kato, Yusuke*; Hayashi, Nobuhiko; Yamauchi, Kunihiko*; Harima, Hisatomo*

Physical Review B, 76(21), p.214514_1 - 214514_8, 2007/12

https://doi.org/10.1103/PhysRevB.76.214514

To determine the superconducting gap function of YNiBC, we calculate the local density of states around a single vortex core with the use of Eilenberger theory and the band structure calculated by local density approximation, assuming various gap structures with point nodes at different positions. We also calculate the angular-dependent heat capacity in the vortex state on the basis of the Doppler-shift method. Comparing our results with the scanning tunneling microscopy and spectroscopy experiment, the angular-dependent heat capacity and thermal conductivity, we propose the gap structure of YNiBC, which has the point nodes and gap minima along . Our gap structure is consistent with all results of angular-resolved experiments.

Non-stoichiometory and vaporization characteristic of LiTiO in hydrogen atmosphere

Hoshino, Tsuyoshi; Yasumoto, Masaru*; Tsuchiya, Kunihiko; Hayashi, Kimio; Nishimura, Hidetoshi*; Suzuki, Akihiro*; Terai, Takayuki*

Fusion Engineering and Design, 82(15-24), p.2269 - 2273, 2007/10

https://doi.org/10.1016/j.fusengdes.2007.07.005

no abstracts in English

SlimCS; Compact low aspect ratio DEMO reactor with reduced-size central solenoid

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

https://doi.org/10.1088/0029-5515/47/8/022

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.

Development of advanced tritium breeders and neutron multipliers for DEMO solid breeder blankets

Tsuchiya, Kunihiko; Hoshino, Tsuyoshi; Kawamura, Hiroshi; Mishima, Yoshinao*; Yoshida, Naoaki*; Terai, Takayuki*; Tanaka, Satoru*; Munakata, Kenzo*; Kato, Shigeru*; Uchida, Munenori*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node294.htm#58596

no abstracts in English