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Journal Articles

Effects of tensile and compressive strain on critical currents of Nb$$_{3}$$Al strand and cable-in-conduit conductor

Kizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; et al.

IEEE Transactions on Applied Superconductivity, 16(2), p.872 - 875, 2006/06

 Times Cited Count:1 Percentile:87.36(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Internally Cu-stabilized RHQT Nb$$_{3}$$Al superconductors with Ta matrix

Takeuchi, Takao*; Tagawa, Kohei*; Noda, Tetsuji*; Banno, Nobuya*; Iijima, Yasuo*; Kikuchi, Akihiro*; Kitaguchi, Hitoshi*; Kosuge, Michio*; Tsuchiya, Kiyosumi*; Koizumi, Norikiyo; et al.

IEEE Transactions on Applied Superconductivity, 16(2), p.1257 - 1260, 2006/06

 Times Cited Count:6 Percentile:60.76(Engineering, Electrical & Electronic)

Next generation nuclear fusion magnets would require a high-current conductor in fields more than 16 T. A CIC conductor of the rapid RHQT processed Nb$$_{3}$$Al may be a promising candidate. Good deformability of intermediately-formed bcc supersaturated-solid solution indeed allowed fabricating such a CIC conductor, which would be subsequently transformation annealed. Ag has been internally included as a basic constituent of a round strand so far, because Ag is almost non-reactive with Nb matrix during the RHQ. However, both of Ag and Nb are not suitable nuclei from the viewpoint of radioactivity when irradiated with neutrons. Recently, we have succeeded in replacing the Nb matrix with Ta that has the advantage of shorter half-life of radioactivity. In the present study, an attempt has been made to replace the Ag internal stabilizer with Cu, in the aim of further reducing radioactivity, based on anticipation that Ta would be less reactive with Cu than Nb did.

Journal Articles

Design study of fusion DEMO plant at JAERI

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:111 Percentile:0.77(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Effective bending strain estimated from $$I$$$$_{c}$$ test results of a D-shaped Nb$$_{3}$$Al CICC coil fabricated with a react-and-wind process for the National Centralized Tokamak

Ando, Toshinari*; Kizu, Kaname; Miura, Yushi*; Tsuchiya, Katsuhiko; Matsukawa, Makoto; Tamai, Hiroshi; Ishida, Shinichi; Koizumi, Norikiyo; Okuno, Kiyoshi

Fusion Engineering and Design, 75-79, p.99 - 103, 2005/11

 Times Cited Count:1 Percentile:88.54(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of advanced superconducting coil technologies for the National Centralized Tokamak

Kizu, Kaname; Miura, Yushi*; Tsuchiya, Katsuhiko; Ando, Toshinari*; Koizumi, Norikiyo; Matsui, Kunihiro*; Sakasai, Akira; Tamai, Hiroshi; Matsukawa, Makoto; Ishida, Shinichi; et al.

Nuclear Fusion, 45(11), p.1302 - 1308, 2005/11

 Times Cited Count:4 Percentile:84.49(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Rapid normal zone propagation observed in a 13 T-46 kA Nb$$_{3}$$Al cable-in-conduit conductor

Koizumi, Norikiyo; Matsui, Kunihiro; Kume, Etsuo; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 15(2), p.1363 - 1366, 2005/06

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

The Nb$$_{3}$$Al Insert was developed by JAERI aiming at the demonstration of a Nb$$_{3}$$Al conductor to fusion reactor magnets. A quench test was performed on the Nb$$_{3}$$Al Insert at 13 T with various temperature margins, which are defined as a difference between current sharing temperature and operating temperature. The initial normalcy was initiated by using an inductive heater and a coil current was kept for several seconds. The normal zone propagation velocity was accelerated after 3 s from the onset of heating in case that the temperature margin was set at 0.5 K. A simulation using one-dimensional stability and quench simulation code was performed. The calculation results indicate that such rapid propagation occurred due to a temperature rise beyond a current sharing temperature because of a large pressure increase even at the location where the normal front did not reach yet. This large pressure rise was caused since the coolant was contained in the closed circulation circuit of the cooling system, which is usually applied to a large magnet cooling system.

Journal Articles

Development of advanced Nb$$_{3}$$Al superconductors for a fusion demo plant

Koizumi, Norikiyo; Takeuchi, Takao*; Okuno, Kiyoshi

Nuclear Fusion, 45(6), p.431 - 438, 2005/06

 Times Cited Count:28 Percentile:30.47(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Development of advanced Nb$$_{3}$$Al superconductors for a fusion demo plant

Koizumi, Norikiyo; Takeuchi, Takao*; Okuno, Kiyoshi

Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11

no abstracts in English

Journal Articles

Application of react-and-wind method to D-shaped test coil using the 20 kA Nb$$_{3}$$Al conductor developed for JT-60SC

Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; Koizumi, Norikiyo; Matsui, Kunihiro; Ando, Toshinari*; Hamada, Kazuya; Hara, Eiji*; Imahashi, Koichi*; Ishida, Shinichi; et al.

IEEE Transactions on Applied Superconductivity, 14(2), p.1535 - 1538, 2004/06

 Times Cited Count:1 Percentile:87.89(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Development of a Nb$$_{3}$$Al 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

Nb$$_{3}$$Sn cConductors have already been developed for the TF coils operating at 13 T. However, the critical current of Nb$$_{3}$$Sn degrades due to a strain, and the amount of degradation becomes larger when the magnetic field increases, which set a limit of the Nb$$_{3}$$Sn application to a large coil at around 13 T. Nb$$_{3}$$Al is considered, therefore, to be a next generation superconductor, since the critical current of Nb$$_{3}$$Al is superior to that of Nb3Sn and less sensitive against strains. JAERI has been developing Nb$$_{3}$$Al conductor since 80s. As the first step, mass production technique of Nb3Al 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 Nb$$_{3}$$Al TF coils for JT-60SC. The prototype Nb$$_{3}$$Al 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.

Journal Articles

Evaluation of strain applied to strands in a 13T-46kA Nb$$_{3}$$Al cable-in-conduit conductor

Koizumi, Norikiyo; Nunoya, Yoshihiko; Matsui, Kunihiro; Nakajima, Hideo; Ando, Toshinari*; Okuno, Kiyoshi

Superconductor Science and Technology, 16(9), p.1092 - 1096, 2003/09

 Times Cited Count:8 Percentile:55.25(Physics, Applied)

A 13T-46kA Nb$$_{3}$$Al insert (ALI) has been developed in the ITER-EDA to demonstrate the applicability of react-and-wind technique to TF coil fabrication. Since it is estimated that a conductor is subjected to 0.4% bending strain after heat treatment when the react-and-wind method is applied, 0.4% bending strain was artificially applied to the ALI conductor. Thus, the conductor is subjected to the thermal and bending strains. The strains due to thermal stress and conductor bending are estimated from the critical current test results of the ALI to be 0.4% and 0%, respectively. The thermal strain showed good agreement with the prediction but the axial strain was not applied to the strand by the 0.4% bending. In addition, the evaluated strain of the Nb$$_{3}$$Al conductor is compared with those of Nb$$_{3}$$Sn conductors. There was an unexpected strain in the Nb$$_{3}$$Sn conductors but the one was not observed in the Nb$$_{3}$$Al conductor. One of the explanations is higher rigidity of the Nb$$_{3}$$Al strand. This shows that an Nb$$_{3}$$Al conductor is suitable to the application to large magnets.

Journal Articles

Pressure drop characteristics of Nb$$_{3}$$Al cable-in-conduit conductor under electromagnetic force; Relation between pressure drop characteristics and cable stiffness

Hamada, Kazuya; Matsui, Kunihiro; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; CS Model Coil Test Group

Teion Kogaku, 38(8), p.417 - 424, 2003/08

As one of the R&D of ITER. a hydraulic performance of Nb$$_{3}$$Al insert coil was measured and compared with other Nb$$_{3}$$Sn conductors. It seems that a longer twist pitch will promote a triangle helium flow space among 4th twist stage cables, jacket and center channel and contribute reduction of pressure drop. Under 500 kN/m of the electromagnetic force, the pressure drop of the Nb$$_{3}$$Al insert decreased by approximately 5%. Nb$$_{3}$$Al conductor indicated quit rigid characteristic under the electromagnetic force and suitable for future magnet with higher magnetic field and current.

Journal Articles

Development of a Nb$$_{3}$$Al conductor to be applied to a fusion reactor and its application to a large superconducting coil

Koizumi, Norikiyo; Okuno, Kiyoshi; Nakajima, Hideo; Ando, Toshinari*; Tsuji, Hiroshi

Teion Kogaku, 38(8), p.391 - 398, 2003/08

no abstracts in English

Journal Articles

Evaluation of the critical current performance of a Nb$$_{3}$$Al insert

Koizumi, Norikiyo; Nunoya, Yoshihiko; Takayasu, Makoto*; Sugimoto, Makoto; Nabara, Yoshihiro; Oshikiri, Masayuki*; CS Model Coil Test Group

Teion Kogaku, 38(8), p.399 - 409, 2003/08

A Nb$$_{3}$$Al insert was developed to demonstrate the applicability of a Nb$$_{3}$$Al conductor and wind-and-react method to a TF coil of a fusion reactor by artificially applying 0.4% bending strain to the conductor after its heat treatment. The critical current test results show that the effective strains applied to the strands is almost zero. Then, the validity of the react-and-wind method was demonstrated. In addition, while an unexpected strain, which was proportional to electromagnetic force, was observed in the same scale Nb$$_{3}$$Sn conductor, such strain did not exist in the Nb$$_{3}$$Al conductor. This shows a Nb$$_{3}$$Al conductor is suitable to the application to large magnets, such as the TF coil. Furthermore, the effect of the current transfer among the strands on the critical current evaluation is studied by developing a numerical analysis code, KORO. The results figure out that the critical current of a large cable-in-conduit conductor can be easily evaluated assuming the uniform current distribution if the conductance among the strands is 10E5 S/m or less.

Journal Articles

Experimental results of ITER Nb$$_{3}$$Al insert; Characteristics of acoustic emission

Ninomiya, Akira*; Arai, Kazuaki*; Takano, Katsutoshi*; Tsugawa, Kazuhito*; Ishigooka, Takeshi*; Kaiho, Katsuyuki*; Nakajima, Hideo; Okuno, Kiyoshi; CS Model Coil Test Group

Teion Kogaku, 38(8), p.425 - 433, 2003/08

no abstracts in English

Journal Articles

AC loss performance of cable-in-conduit conductor; Influence of cable mechanical property on coupling loss reduction

Matsui, Kunihiro; Takahashi, Yoshikazu; Koizumi, Norikiyo; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; CS Model Coil Test Group

Teion Kogaku, 38(8), p.410 - 416, 2003/08

The test of the ITER Central Solenoid (CS) model coil, CS and Nb$$_{3}$$Al inserts was carried. The AC loss measurement is one of the most important tests to determine coil performance. The coupling losses of CS and Nb$$_{3}$$Al inserts were measured by calorimetric and magnetization methods, respectively. Both coils had coupling losses with many coupling time constant, and induced circulation currents were observed by voltage taps and hall sensors. Coupling losses decreased with exponential decay constants since the electromagnetic force broke weak sinter among the strands. The gap, created between the cable and the conduit by electromagnetic force, is dependent on the pressure drop of the coolant that flows in the conductor. Our analysis shows that the exponential decay constant of coupling losses is dependent on the gap size. If we can evaluate this exponential decay constant and apply the electromagnetic force that corresponds for the exponential decay constant to the conductor before the regular operation, we can use coils of the condition that coupling losses decrease on the operation.

Journal Articles

Development of the Nb$$_{3}$$Al D-shaped coil fabricated by react-and-wind method for JT-60 superconducting Tokamak

Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; Koizumi, Norikiyo; Matsui, Kunihiro; Ando, Toshinari*; Hamada, Kazuya; Hara, Eiji*; Imahashi, Koichi*; Ishida, Shinichi; et al.

Proceedings of 6th European Conference on Applied Superconductivity (EUCAS 2003), p.400 - 407, 2003/00

Toroidal field coils (TFC) of the JT-60SC consist of 18 D-shape coils. The maximum magnetic field is 7.4 T at an operational current of 19.4 kA. An advanced Nb$$_{3}$$Al superconductor was developed for the TFC conductor material in JAERI. The Nb$$_{3}$$Al has lower strain sensitivity on superconducting performances, and allows us to fabricate the TFC by react-and-wind (R&W) method that makes that the coil fabrication with high reliability becomes easier and the fabrication cost becomes lower. To demonstrate the coil fabrication by R&W method, a two-turn D-shape coil was developed. The D-shape coil was tested at 4.3-4.4K and 7-12T. Measured critical current (Ic) was 30 kA at 7.3 T and 4.4 K. Using the measured conductor and strand Ic values, the strain of the conductor was estimated to be -0.6%. The Ic-B-T characteristic expected by an empirical equation substituting this strain shows that the required temperature margin for TFC is satisfied. Thus, the R&W method was demonstrated to be the applicable fabrication method of the TFC.

JAEA Reports

Nb$$_3$$Al insert experiment log book; 3rd Experiment of CS model coil

Sugimoto, Makoto; Koizumi, Norikiyo; Isono, Takaaki; Matsui, Kunihiro; Nunoya, Yoshihiko; Tsutsumi, Fumiaki*; Oshikiri, Masayuki*; Wakabayashi, Hiroshi*; Okuno, Kiyoshi; Tsuji, Hiroshi

JAERI-Tech 2002-080, 100 Pages, 2002/11

JAERI-Tech-2002-080.pdf:7.89MB

The cool down of CS model coil and Nb$$_3$$Al insert was started on March 4, 2002. It took almost one month and immediately started coil charge since April 3, 2002. The charge test of Nb$$_3$$Al insert and CS model coil was completed on May 2, 2002. All of the experiments including the warm up was also completed on May 30, 2002.In this campaign, total shot numbers were 102 and the size of the data file in the DAS (Data Acquisition System) was about 5.2 GB. This report is a database that consists of the log list and the log sheets of every shot.

Journal Articles

Critical current test results of 13T-46kA Nb$$_{3}$$Al cable-in-conduit conductor

Koizumi, Norikiyo; Takahashi, Yoshikazu; Nunoya, Yoshihiko; Matsui, Kunihiro; Ando, Toshinari; Tsuji, Hiroshi; Okuno, Kiyoshi; Azuma, Katsunori*; Fuchs, A.*; Bruzzone, P.*; et al.

Cryogenics, 42(11), p.675 - 690, 2002/11

 Times Cited Count:22 Percentile:34.52

In the framework of ITER-EDA, a 13 T – 46 kA Nb$$_{3}$$Al conductor with stainless steel jacket has been developed to demonstrate applicability of an Nb$$_{3}$$Al conductor with react-and-wind technique to ITER-TF coils. The critical current performances of the Nb$$_{3}$$Al conductors were studied to verify that the conductor achieves the expected performance and 0.4% bending strain does not originate degradation. The critical currents were measured at the background magnetic fields of 7, 9, 10 and 11 T at the temperatures from 6 to 9 K. The expected critical currents is calculated using the developed model and the calculation results indicate that the experimental results showed good agreement with the expected critical currents. Accordingly, we can conclude that the fabrication process of this conductor was appropriate and the applicability of the react-and-wind technique was demonstrated.

Journal Articles

The Strain and temperature scalling law for the critical current density of a jelly-roll Nb$$_{3}$$Al strand in high magnetic fields

Keys, S.*; Koizumi, Norikiyo; Hampshire, D.*

Superconductor Science and Technology, 15(7), p.991 - 1010, 2002/07

 Times Cited Count:35 Percentile:18.41(Physics, Applied)

The critical current density of a jelly-roll Nb$$_{3}$$Al strand was measured at first as a function of magntic field, temperature and strain. The equation to estimate its critical current density has been derived from these test results. The magenti fields, temperatures and strains were less than 15 T, less than 14 K and -1.8 - 0.7% in the experiment.

54 (Records 1-20 displayed on this page)