Preliminary result of validation study in SAS-SFR (SAS4A) code in simulated top and undercooled overpower conditions

Kawada, Kenichi; Takahashi, Katsuhiko*; Tobita, Yoshiharu

Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 10 Pages, 2014/12

Quench detection of fast plasma events for the JT-60SA central solenoid

Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Kamiya, Koji; Takahashi, Yoshikazu; Yoshida, Kiyoshi

Fusion Engineering and Design, 87(1), p.23 - 29, 2012/01

https://doi.org/10.1016/j.fusengdes.2011.08.005

The JT-60 is planned to be modified to a full-superconducting tokamak. The maximum temperature of the magnet during its quench might reach the temperature of higher than several hundreds Kelvin that will damage the magnet itself. The high precision quench detection system, therefore, is important in the protection system. The disk-shaped pickup coils are inserted in the CS module for quench detection. Thus we improved the analysis model to evaluate the applicability of the disk-shaped pickup coils to quench detection system during the fast plasma event, such as disruption, by introducing the passive coil series such as vacuum vessel and stabilizer. The analysis results show that the disk-shaped pickup coil is applicable whenever the standard operation and fast plasma event. Additionally, the pickup coil design method is also modified to reduce the total cost of protection system. In this paper, the improved analysis method, modified design method and those results are described.

Innovative alpha radioactivity monitor for clearance level inspection based on ionized air transport technology; CFD-simulated and experimental ion transport efficiencies for uranium-attached pipes

Hirata, Yosuke*; Nakahara, Katsuhiko*; Sano, Akira*; Sato, Mitsuyoshi*; Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

Journal of Power and Energy Systems (Internet), 2(2), p.561 - 572, 2008/00

https://doi.org/10.1299/jpes.2.561

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.

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

https://doi.org/10.1088/0029-5515/46/3/S05

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.

Fracture mechanics analysis including the butt joint geometry for the superconducting conductor conduit of the national centralized tokamak

Takahashi, Hiroyuki*; Kudo, Yusuke; Tsuchiya, Katsuhiko; Kizu, Kaname; Ando, Toshinari*; Matsukawa, Makoto; Tamai, Hiroshi; Miura, Yukitoshi

Fusion Engineering and Design, 81(8-14), p.1005 - 1011, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.07.028

This paper presents dependence of the stress intensity factor, around the defect in the butt joint welding of a superconducting conductor conduit, on a geometrical factor estimated by fracture mechanics analysis. The stress intensity factor can be estimated by the Newman-Raju equation about CICC section, but the effect of the difference between the geometry assumed in the equation and CICC has not been clarified yet. Therefore, the three-dimensional finite element method (3D-FEM) is performed to estimate the geometrical factor. As a result, the Newman-Raju equation is considered to be available for the assessment of the fracture toughness of the conduit of rectangular shape because the maximum stress intensity factor by 3-D FEM is only 3% larger than that by the Newman-Raju equation in the maximum postulated defect.

Development of a NbAl conductor for toroidal field coils

Koizumi, Norikiyo; Ando, Toshinari*; Nakajima, Hideo; Matsui, Kunihiro; Sugimoto, Makoto; Takahashi, Yoshikazu; Okuno, Kiyoshi; Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; et al.

Proceedings of 20th IEEE/NPSS Symposium on Fusion Engineering (SOFE 2003), p.419 - 422, 2003/10

NbSn cConductors have already been developed for the TF coils operating at 13 T. However, the critical current of NbSn degrades due to a strain, and the amount of degradation becomes larger when the magnetic field increases, which set a limit of the NbSn application to a large coil at around 13 T. NbAl is considered, therefore, to be a next generation superconductor, since the critical current of NbAl is superior to that of NbSn and less sensitive against strains. JAERI has been developing NbAl conductor since 80s. As the first step, mass production technique of NbAl strands was established. In the second step, coil fabrication technique was developed and could successfully be charged to the nominal point of 13 T and 46 kA. From these advantages, JAERI is also promoting R&D activities to develop NbAl TF coils for JT-60SC. The prototype NbAl conductor has already been made. A D-shaped coil was fabricated and successfully tested. These activities constitute the basic approaches to develop TF coils whose operating field is expected to be around 16 T.

Development and performance evaluation of 13T-46kA NbAl conductor

Koizumi, Norikiyo; Ando, Toshinari; Takahashi, Yoshikazu; Matsui, Kunihiro; Nakajima, Hideo; Tsuchiya, Yoshinori; Kikuchi, Kenji; Nunoya, Yoshihiko; Kato, Takashi; Isono, Takaaki; et al.

Senshin A15-gata Kagobutsu Chodendo Senzai Shimpojiumu Rombunshu, p.5 - 9, 2000/00

no abstracts in English

Cool-down and charging tests of a double-conduit type forced-flow superconducting coil

Takahashi, Yoshikazu; Yoshida, Kiyoshi; Tsuji, Hiroshi; *; *; *; *; *; Takahashi, Ryukichi*; Asano, Katsuhiko*; et al.

Proc. of 16th Int. Cryogenic Engineering Conf. /Int. Cryogenic Materials Conf., 0, p.811 - 814, 1996/00

no abstracts in English

Alpha radioactivity measurement based on ionized air transportation technology, 17; 3D-CFD simulations of uranium waste

Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Hirata, Yosuke*; Naito, Susumu*; Sano, Akira*; Nakahara, Katsuhiko*; Sato, Mitsuyoshi*; Nambu, Kenichi*; Takahashi, Hiroyuki*; et al.

no journal, , 

no abstracts in English