Estimation of the paleostress field from the 3-D orientation distribution of microcracks and their geothermal conditions in the Toki Granite, central Japan

Takagi, Hideo*; Miwa, Shigenori*; Yokomizo, Yoshiyuki*; Nishijima, Kei*; Enjoji, Mamoru*; Mizuno, Takashi; Amano, Kenji

Chishitsugaku Zasshi, 114(7), p.321 - 335, 2008/07

https://doi.org/10.5575/geosoc.114.321

Based on the 3-D orientations of intracrystalline healed, sealed and open extension microcracks in quartz grains in the Late Cretaceous Toki Granite, we discuss the paleostress field and the history of microcracking combining the microthermometry of fluid inclusions in healed microcracks and sealing material identification in sealed microcracks. Twenty one oriented samples are collected mainly from the DH-15 core (240-1000 mabh) drilled by Japan Atomic Energy Agency (JAEA) and additionally from five outcrops in the Tono region. 3-D orientations of healed microcracks indicate the orientation of N-S to NW-SE in almost all sites, whereas those of sealed and open microcracks indicate the dominant orientation of E-W. Two or three orthogonal sets of microcracks are common in both healed and sealed microcracks. The formation of these sets can be attributed to the switch of principal stress axis due to stress release just after the crack formation. Healed microcracks probably reflect more regional paleostress field because of consistency of the orientations than the case of sealed and open microcracks that show rather scattering orientations. N-S to NW-SE trending healed microcracks are formed around 60 Ma on the basis of K-Ar biotite ages of the Toki Granite and formation temperature (c. 300-400C) of fluid inclusions estimated from microthermometry in the case of intrusion depth (3.5 km=100 MPa) of the Toki Granite. Thus the orientation trended NW-SE after the restoration of clockwise rotation of SW Japan at c. 15 Ma. Following the healed microcrack formation, E-W trending high-angle sealed microcracks filled with carbonate mineral are formed. Open microcracks presumably formed at near-surface at the last stage of sealed microcrack formation after c. 20 Ma before the Mizunami Group deposited unconformably on the granite.

Evaluation method of critical current and current sharing temperature for large-current Cable-in-Conduit conductors

Nunoya, Yoshihiko; Isono, Takaaki; Sugimoto, Makoto; Takahashi, Yoshikazu; Nishijima, Gen*; Matsui, Kunihiro; Koizumi, Norikiyo; Ando, Toshinari*; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 13(2), p.1404 - 1407, 2003/06

https://doi.org/10.1109/TASC.2003.812679

Analysis of critical current () and current sharing temperature () was performed to the ITER Center Solenoid (ITER-CS) Model Coil Insert. Voltage behavior related to normal state transition of the conductor during or measurement has not been well understood especially in case of such a large cable with more than one thousand strands as this coil. From the detailed analysis of the voltage behavior of the coil, it is found that the average of electric field in the strand-longitudinal direction over the conductor cross section is equal to the average field of one strand along the conductor length, whose integral was measured by the voltage taps during the coil test. It is because twist pitch of the cable is less than the range of longitudinal field variation in this case. This evaluation method can estimate voltage behavior and predict and values, which are important parameters for the design of a large conductor coil, based on the property of strands composing the conductor.

Evaluation of critial current performance of 13 T-46 kA steel-jacketed NbAl conductor

Koizumi, Norikiyo; Azuma, Katsunori*; Tsuchiya, Yoshinori; Matsui, Kunihiro; Takahashi, Yoshikazu; Nakajima, Hideo; Nishijima, Gen; Nunoya, Yoshihiko; Ando, Toshinari; Isono, Takaaki; et al.

Fusion Engineering and Design, 58-59, p.1 - 5, 2001/11

https://doi.org/10.1016/S0920-3796(01)00465-3

no abstracts in English

Critical current and sharing temperature of the ITER-CS insert coil

Nunoya, Yoshihiko; Isono, Takaaki; Sugimoto, Makoto; Takahashi, Yoshikazu; Ando, Toshinari; Nishijima, Gen; CS Model Coil Test Group

Teion Kogaku, 36(6), p.354 - 360, 2001/06

https://doi.org/10.2221/jcsj.36.354

no abstracts in English

Design of a 60-kA HTS current lead for fusion magnets and its R&D

Ando, Toshinari; Isono, Takaaki; Hamada, Kazuya; Nishijima, Gen; Tsuji, Hiroshi; Tomioka, Akira*; Bono, Takaaki*; Yasukawa, Yukio*; Konno, Masayuki*; Uede, Toshio*

IEEE Transactions on Applied Superconductivity, 11(1), p.2535 - 2538, 2001/03

https://doi.org/10.1109/77.920383

no abstracts in English

CS model coil experiment log book

Isono, Takaaki; Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi*; Tsuji, Hiroshi

JAERI-Tech 2000-084, 393 Pages, 2001/02

JAERI-Tech-2000-084.pdf:16.39MB

no abstracts in English

Development of a 13T-640MJ superconducting pulsed coil for fusion machines

Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Isono, Takaaki; Sugimoto, Makoto; Kawano, Katsumi; Koizumi, Norikiyo; Nunoya, Yoshihiko; et al.

Denki Gakkai Rombunshi, B, 120(3), p.449 - 456, 2000/03

no abstracts in English

Completion of the ITER CS model coil-outer module fabrication

Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Isono, Takaaki; Sugimoto, Makoto; Kawano, Katsumi; Koizumi, Norikiyo; Nunoya, Yoshihiko; et al.

IEEE Transactions on Applied Superconductivity, 10(1), p.568 - 571, 2000/03

https://doi.org/10.1109/77.828298

no abstracts in English

An Evaluation of the inlet flow reduction for a cable conduit conductor by rapid heating

Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Nishijima, Gen; Matsui, Kunihiro; Nunoya, Yoshihiko; Takahashi, Yoshikazu; Tsuji, Hiroshi

Cryogenics, 39(11), p.939 - 945, 1999/11

https://doi.org/10.1016/S0011-2275(99)00129-0

no abstracts in English

Neutron irradiation effect on superconducting magnet materials

Nishimura, Arata*; Takeuchi, Takao*; Nishijima, Shigehiro*; Ochiai, Kentaro; Takakura, Kosuke; Shikama, Tatsuo*; Sato, Isamu*; Watanabe, Kazuo*; Nishijima, Gen*

no journal, , 

no abstracts in English