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Journal Articles

Fano factor evaluation of diamond detectors for alpha particles

Shimaoka, Takehiro*; Kaneko, Junichi*; Sato, Yuki; Tsubota, Masakatsu*; Shimmyo, Hiroaki*; Chayahara, Akiyoshi*; Watanabe, Hideyuki*; Umezawa, Hitoshi*; Mokuno, Yoshiaki*

Physica Status Solidi (A), 213(10), p.2629 - 2633, 2016/10

 Times Cited Count:1 Percentile:91.03(Materials Science, Multidisciplinary)

Journal Articles

Non-destructive examination of jacket sections for ITER central solenoid conductors

Takahashi, Yoshikazu; Suwa, Tomone; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200904_1 - 4200904_4, 2015/06

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

The Japan Atomic Energy Agency (JAEA) is responsible for procuring all amounts of Central Solenoid (CS) Conductors for ITER, including CS jacket sections. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A total of 576 Nb$$_{3}$$Sn strands and 288 copper strands are cabled around the central spiral. The maximum operating current is 40 kA at magnetic field of 13 T. CS jacket section is circular in square type tube made of JK2LB, which is high manganese stainless steel with boron added. Unit length of jacket sections is 7 m and 6,300 sections will be manufactured and inspected. Outer/inner dimension and weight are 51.3/35.3 mm and around 90 kg, respectively. Eddy Current Test (ECT) and Phased Array Ultrasonic Test (PAUT) were developed for non-destructive examination. The defects on inner and outer surfaces can be detected by ECT. The defects inside jacket section can be detected by PAUT. These technology and the inspected results are reported in this paper.

Journal Articles

Behavior of Nb$$_{3}$$Sn cable assembled with conduit for ITER central solenoid

Nabara, Yoshihiro; Suwa, Tomone; Takahashi, Yoshikazu; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Sakurai, Takeru; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200305_1 - 4200305_5, 2015/06

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

Journal Articles

Fabrication process qualification of TF Insert Coil using real ITER TF conductor

Ozeki, Hidemasa; Isono, Takaaki; Kawano, Katsumi; Saito, Toru; Kawasaki, Tsutomu; Nishino, Katsumi; Okuno, Kiyoshi; Kido, Shuichi*; Semba, Tomoyuki*; Suzuki, Yozo*; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200804_1 - 4200804_4, 2015/06

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

Journal Articles

Optimization of heat treatment of Japanese Nb$$_3$$Sn conductors for toroidal field coils in ITER

Nabara, Yoshihiro; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Suwa, Tomone; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Koizumi, Norikiyo; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.6000605_1 - 6000605_5, 2014/06

no abstracts in English

Journal Articles

Investigation of strand bending in the He-inlet during reaction heat treatment for ITER TF Coils

Hemmi, Tsutomu; Matsui, Kunihiro; Kajitani, Hideki; Okuno, Kiyoshi; Koizumi, Norikiyo; Ishimi, Akihiro; Katsuyama, Kozo

IEEE Transactions on Applied Superconductivity, 24(3), p.4802704_1 - 4802704_4, 2014/06

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA), as Japan Domestic Agency, has responsibility to procure nine ITER Toroidal Field (TF) coils. The TF coil winding consists of a Nb$$_{3}$$Sn Cable-In-Conduit conductor, a pair of joints and a He-inlet. The current capacity of 68 kA is required at the magnetic field of 7 T around the He-inlet region in the TF coil winding. During reaction heat-treatment, the compressive residual strain in Nb$$_{3}$$Sn cable is induced by the difference in the thermal expansion coefficients between the Nb$$_{3}$$Sn cable and stainless steel jacket. The strands bending in the Nb$$_{3}$$Sn cable of the He-inlet is anticipated since there is the compressive residual strain and a gap between the Nb$$_{3}$$Sn cable and the He-inlet to introduce SHE flow. If the strand is bent, the variation of mechanical behaviors, such as the elongation of He-inlet during the reaction heat-treatment and the thermally induced residual strain on the jacket around the He-inlet, are expected. To investigate the strands bending in the Nb$$_{3}$$Sn cable of the He-inlet, the following items are performed; (1) elongation measurement during reaction heat-treatment, (2) residual longitudinal strain measurement using strain gauges by sample cuttings, (3) nondestructive inspection on the cable and strands using high resolution X-ray CT, Detail of test results and investigation of the strands bending in the Nb$$_{3}$$Sn cable of the He-inlet are reported and discussed.

Journal Articles

Cabling technology of Nb$$_3$$Sn conductor for ITER central solenoid

Takahashi, Yoshikazu; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Uno, Yasuhiro; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4802404_1 - 4802404_4, 2014/06

 Times Cited Count:17 Percentile:25.67(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is procuring all amounts of Nb$$_3$$Sn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The original design of cabling twist pitches is 45-85-145-250-450 mm, called normal twist pitch (NTP). The test results of the conductors with NTP was that current shearing temperature (Tcs) is decreasing due to electro-magnetic (EM) load cycles. On the other hand, the results of the conductors with short twist pitches (STP) of 25-45-80-150-450 mm show that the Tcs is stabilized during EM load cyclic tests. Because the conductors with STP have smaller void fraction, higher compaction ratio during cabling is required and possibility of damage on strands increases. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies will be described in this paper.

Journal Articles

Cryogenic structures of superconducting coils for fusion experimental reactor "ITER"

Nakajima, Hideo; Shimamoto, Susumu*; Iguchi, Masahide; Hamada, Kazuya; Okuno, Kiyoshi; Takahashi, Yoshikazu

Teion Kogaku, 48(10), p.508 - 516, 2013/10

JAEA is procuring both structural materials and structural design of Toroidal Field (TF) coil and Central Solenoid (CS) for ITER. Although 316LN is used in the most parts of the superconducting magnets system, the cryogenic stainless steels, JJ1 and JK2LB, which were newly developed by JAEA and Japanese steel companies, are used in the highest stress area of TF coil case and whole CS conductor jackets, respectively. These two materials became commercially available based on demonstration of productivity and weldability of materials, and evaluations of 4 K mechanical properties of trial products including welded parts. In order to simplify quality control in mass production, JAEA has used materials specified in the material section of "Codes for Fusion Facilities - Rules on Superconducting Magnet Structure (2008)" issued by the Japan Society of Mechanical Engineers (JSME). The design of structural materials, production technology and quality control are described in this paper.

Journal Articles

Cable twist pitch variation in Nb$$_{3}$$Sn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Nabara, Yoshihiro; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Hamada, Kazuya; Matsui, Kunihiro; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 23(3), p.4801504_1 - 4801504_4, 2013/06

 Times Cited Count:11 Percentile:40.69(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is the first to start the mass production of the TF conductors in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The height and width of the TF coils are 14 m and 9 m, respectively. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A circular multistage superconducting cable is inserted into a circular stainless steel jacket with a thickness of 2 mm. A total of 900 Nb$$_{3}$$Sn strands and 522 copper strands are cabled around the central spiral and the cable is inserted into a round-in-round stainless steel jacket. It was observed that the cabling pitch of the destructive sample is longer than the original pitch at cabling. The JAEA carried out the tensile tests of the cable and the measurement of the cable rotation during the insertion to investigate the cause of the elongation. The cause of elongation was clarified and the results will be described in this paper.

Journal Articles

Examination of Nb$$_{3}$$Sn conductors for ITER central solenoids

Nabara, Yoshihiro; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; Takahashi, Yoshikazu; Matsui, Kunihiro; Koizumi, Norikiyo; et al.

IEEE Transactions on Applied Superconductivity, 23(3), p.4801604_1 - 4801604_4, 2013/06

 Times Cited Count:7 Percentile:53.75(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Risk assessment for ITER TF coil manufacturing

Ueno, Kenichi; Matsui, Kunihiro; Nishino, Toru; Isono, Takaaki; Okuno, Kiyoshi

Plasma and Fusion Research (Internet), 8(Sp.1), p.2405062_1 - 2405062_5, 2013/05

Japan Domestic Agency (JADA) for ITER will procure toroidal field (TF) coil structures and winding packs, and assemble them into a final TF coil configuration. Because the manufacturing schedule of the TF coils is on a critical path toward the first plasma of ITER, coil manufacturing must be successful and proceed on schedule. Therefore, risk assessment and management for the manufacturing are vital. JADA performed a risk assessment on the basis of past manufacturing experiences and risk mitigation policy for ITER. The results show that risks can be mitigated to a level that we can assure sufficint quality of the TF coil by sound design, manufacturing and quality management processes developed through R&D activities, and the use of prototypes.

Journal Articles

ITER magnet systems; From qualification to full scale construction

Nakajima, Hideo; Hemmi, Tsutomu; Iguchi, Masahide; Nabara, Yoshihiro; Matsui, Kunihiro; Chida, Yutaka; Kajitani, Hideki; Takano, Katsutoshi; Isono, Takaaki; Koizumi, Norikiyo; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03

The ITER organization and 6 Domestic Agencies (DA) have been implementing the construction of ITER superconducting magnet systems. Four DAs have already started full scale construction of Toroidal Field (TF) coil conductors. The qualification of the radial plate manufacture has been completed, and JA and EU are ready for full scale construction. JA has qualified full manufacturing processes of the winding pack with a 1/3 prototype and made 2 full scale mock-ups of the basic segments of TF coil structure to optimize and industrialize the manufacturing process. Preparation and qualification of the full scale construction of the TF coil winding is underway by EU. Procurement of the manufacturing equipment is near completion and qualification of manufacturing processes has already started. The constructions of other components of the ITER magnet systems are also going well towards the main goal of the first plasma in 2020.

Journal Articles

Mass production of Nb$$_{3}$$Sn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4801904_1 - 4801904_4, 2012/06

 Times Cited Count:7 Percentile:52.58(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency is the first to start the mass production of the TF conductors in Phase IV in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The conductor is cable-in-conduit conductor with a central spiral. A total of 900 Nb$$_{3}$$Sn strands and 522 copper strands are cabled around the central spiral and then wrapped with stainless steel tape whose thickness is 0.1 mm. Approximately 60 tons of Nb$$_{3}$$Sn strands were manufactured by the two suppliers in December 2010. This amount corresponds to approximately 55% of the total contribution from Japan. Approximately 30% of the total contribution from Japan was completed as of February 2011. JAEA is manufacturing one conductor per month under a contract with two Japanese companies for strands, one company for cabling and one company for jacketing. This paper summarizes the technical developments including a high-level quality assurance. This progress is a significant step in the construction of the ITER machine.

Journal Articles

Examination of Japanese mass-produced Nb$$_3$$Sn conductors for ITER toroidal field coils

Nabara, Yoshihiro; Nunoya, Yoshihiko; Isono, Takaaki; Hamada, Kazuya; Takahashi, Yoshikazu; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Ebisawa, Noboru; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4804804_1 - 4804804_4, 2012/06

 Times Cited Count:14 Percentile:34.03(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Technology development and mass production of Nb$$_{3}$$Sn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

Nuclear Fusion, 51(11), p.113015_1 - 113015_11, 2011/11

 Times Cited Count:10 Percentile:51.15(Physics, Fluids & Plasmas)

Japan Atomic Energy Agency is procuring the Nb$$_{3}$$Sn superconductors for Toroidal Field (TF) Coils under the ITER project. Because manufacturing amount of Nb$$_{3}$$Sn strands is quite large compared with the past experience and required superconducting performance is higher than that of the model coils which have been fabricated and tested in the ITER-EDA, quality control technique is very important for the manufacture of the strands. Sophisticated control technique is also required for the jacketing, in order to fabricate the conductors with the precise outer diameter and without leakage at welding part. This paper summarizes the technical developments leading to the first successful mass production of ITER TF conductors.

Journal Articles

First qualification of ITER toroidal field coil conductor jacketing

Hamada, Kazuya; Takahashi, Yoshikazu; Isono, Takaaki; Nunoya, Yoshihiko; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Tsutsumi, Fumiaki; Koizumi, Norikiyo; Nakajima, Hideo; et al.

Fusion Engineering and Design, 86(6-8), p.1506 - 1510, 2011/10

 Times Cited Count:9 Percentile:33.72(Nuclear Science & Technology)

Japan Atomic Energy Agency has a responsibility for procurement of the ITER toroidal field coil conductors as Japanese Domestic Agency (JADA) of the ITER project. The TF conductor is a circular shaped cable-in-conduit conductor, which is composed of cable and stainless steel conduit (jacket). The outer diameter and wall thickness of jacket are 43.7mm and 2mm, respectively. The cable consists of 900 Nb$$_{3}$$Sn superconducting strands and 522 Cu strands. The length of TF conductor is 780m in maximum. Preparation of conductor fabrication was completed in December 2009. And then, to demonstrate a conductor manufacturing procedure, JADA fabricated 780m-long Cu dummy conductor as a process qualification. Finally, the 780m-long Cu dummy conductor has been successfully completed, ahead of other domestic agencies that are in charge of TF conductor procurement. Since all of manufacturing processes have been qualified, JADA started to fabricate superconducting conductors for TF coils.

Journal Articles

Development of superconducting technology for fusion application in the world

Okuno, Kiyoshi; Takahashi, Yoshikazu; Koizumi, Norikiyo; Nakajima, Hideo

Heisei-23-Nen Denki Gakkai Zenkoku Taikai Koen Rombunshu, 5, p.S1(34) - S1(37), 2011/03

When we talk about the history and future perspective of superconducting technology, we recognize its important relation to fusion research. Magnetic confinement fusion devices, represented by a tokamak and helical systems, promoted the scale-up in size, high field and high performances of superconducting magnets, together with the production of superconductors at industry level. ITER will play this role in the first quarter of the 21st century. The construction of ITER has already started in Cadarache, France, with a milestone to obtain the 1st plasma in November 2019. The ITER participants have started their procurement activities for superconducting magnets to achieve this milestone. This is being performed with the highest superconducting technology at present and will bring a major progress in this area when completed.

Journal Articles

Technology development for the manufacture of Nb$$_{3}$$Sn conductors for ITER Toroidal Field coils

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

Japan Atomic Energy Agency is procuring the Nb$$_{3}$$Sn superconductors for Toroidal Field (TF) coils under the ITER project. Because manufacturing amount of Nb$$_{3}$$Sn strands is quite large compared with the past experience and required superconducting performance is higher than that of the model coils which have been fabricated and tested in the ITER-EDA, quality control technique is very important for the manufacture of the strands. Sophisticated control technique is also required for the jacketing, in order to fabricate the conductors with the precise outer diameter and without leakage at welding part. Cu dummy conductor with full length (760 m) has been fabricated successfully and all jacketing technology was confirmed through this fabrication. The fabrication of the Nb$$_{3}$$Sn conductor for TF coils will start in March 2010.

Journal Articles

Neutronic analysis of fusion tokamak devices by PHITS

Sukegawa, Atsuhiko; Takiyoshi, Koji*; Amano, Toshio*; Kawasaki, Hiromitsu*; Okuno, Koichi*

Progress in Nuclear Science and Technology (Internet), 1, p.36 - 39, 2011/02

A complete 3D radiation shielding analysis by PHITS has been performed for the JT-60U and JT-60 superconducting tokamak device (JT-60SA) in the present study. The PHITS has been developed for high energy particles physics in Japan. The neutron and photon transport analysis less than 20 MeV with the general cross section library is the same algorism of MCNP-4C code. The monoenergetic neutron (E$$_{rm n}$$ = 2.45 MeV) of the DD fusion devices are used for the neutron source in the analysis. The neutron source distribution are available a toroidally symmetric source for the analysis. The toroidal source has a poloidal distribution, so that a source routine in the PHITS has been replaced a newly developed source routine. The visual nuclear responses such as the neutron flux distribution, the photon flux distribution, the nuclear heating of the coils and the dose rate around the devices has been calculated by the PHITS for the fusion tokamak devices. Initial results by the PHITS have been demonstrated.

Journal Articles

Procurement of Nb$$_3$$Sn superconducting conductors in ITER

Nabara, Yoshihiro; Isono, Takaaki; Nunoya, Yoshihiko; Koizumi, Norikiyo; Hamada, Kazuya; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Uno, Yasuhiro*; Seki, Shuichi*; et al.

Journal of Plasma and Fusion Research SERIES, Vol.9, p.270 - 275, 2010/08

288 (Records 1-20 displayed on this page)