A New model to simulate critical current degradation of a large CICC by taking into account strand bending

Koizumi, Norikiyo; Nunoya, Yoshihiko; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 16(2), p.831 - 834, 2006/06

https://doi.org/10.1109/TASC.2005.869640

no abstracts in English

Development of 10kA Bi2212 conductor for fusion application

Isono, Takaaki; Nunoya, Yoshihiko; Ando, Toshinari*; Okuno, Kiyoshi; Ono, Michitaka*; Ozaki, Akira*; Koizumi, Tsutomu*; Otani, Nozomu*; Hasegawa, Takayo*

IEEE Transactions on Applied Superconductivity, 13(2), p.1512 - 1515, 2003/06

https://doi.org/10.1109/TASC.2003.812763

Japan Atomic Energy Research Institute has started development work on a large current conductor using high Tc superconductor (HTS) aiming at a fusion power reactor after the International Thermonuclear Experimental Reactor (ITER). HTS has a capability to produce a magnetic field of higher than 16 T, which is required in such a fusion power reactor. A trial fabrication of a 10-kA 12-T conductor was started using round Ag-alloy sheathed Bi-2212 strands, which has best performance at 4.2K, 16T at present. The conductor has about 34-mm diameter, and is composed of 729 HTS strands. Operating temperature is designed at not only 4 K but also 20K. The conductor sample is indirectly cooled and is solder-coated on the surface to use specific heat of the lead as much as possible, which at 20 K is almost comparable with specific heat of SHe at 4.5K, 0.6MPa. From the tests of the conductor, the fabrication of large HTS conductor and 10kA operation at 12 T and about 12.5 K were successfully performed and the possibility of HTS to use fusion application was demonstrated.

Critical current test results of 13T-46kA NbAl 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

https://doi.org/10.1016/S0011-2275(02)00128-5

In the framework of ITER-EDA, a 13T-46kA NbAl conductor with stainless steel jacket has been developed to demonstrate applicability of an NbAl conductor with react-and-wind technique to ITER-TF coils. The critical current performances of the NbAl 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.

Temperature and magnetic field dependence of the critical current density for a mass-produced NbAl multifilamentary strand fabricated by a jelly-roll method

Takahashi, Yoshikazu; Koizumi, Norikiyo; Nunoya, Yoshihiko; Takaya, Yoshiyuki*; Tsuji, Hiroshi

IEEE Transactions on Applied Superconductivity, 12(2), p.1799 - 1803, 2002/06

https://doi.org/10.1109/TASC.2002.1020340

JAERI has been developing jelly-roll processed multifilamentary NbAl/Cu strands for the Toroidal Field (TF) coils of fusion tokamak machines since 1986, in cooperation with industries. One ton of mass-produced strands were successfully manufactured for the 13T-46kA NbAl insert which will be tested using the ITER Central Solenoid model coil. The critical current of the Nb3Al strand developed for the ITER project was measured in temperatures from 4.2 K to 15 K and in applied magnetic fields up to 16 T. An empirical equation for the critical current density was devised using these data and the pinning force scaling method. Good agreement between this equation and the measured data is obtained in the operating condition of the ITER machine. The equation is useful in evaluating the performance of the full-size conductor that consists of 1,152 strands and in establishing the optimum design criteria for the conductor in fusion machines.

Change in superconducting properties of BiSrCaCuO single crystals by Kr-ion irradiation followed by thermal annealing

Ogikubo, Koji*; Uchida, Yukihiro*; Terai, Takayuki*; Yamaguchi, Kenji*; Yamawaki, Michio*; Hayashi, Kimio

Tokyo Daigaku Kogakubu Sogo Shikenjo Nempo, 59, p.91 - 95, 2000/12

no abstracts in English

Parallel and crossed columnar defects aligned at 45° to the c axis in BiSrCaCuO tapes

Kazumata, Yukio*; Okayasu, Satoru; Sataka, Masao;

Physical Review B, 58(9), p.5839 - 5847, 1998/09

https://doi.org/10.1103/PhysRevB.58.5839

no abstracts in English

Improvement of CHF correlations for research reactors using plate-type fuels

Kaminaga, Masanori; Yamamoto, Kazuyoshi; Sudo, Yukio

Proceedings of 8th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), Vo.3, p.1815 - 1822, 1997/00

In research reactors, plate-type fuel elements are generally adopted so as to produce high power densities and are cooled by a downward flow. A core flow reversal from a steady-state forced downward flow to an upward flow due to natural convection should occur during operational transients such as "Loss of the primary coolant flow". Therefore, in the thermal hydraulic design of research reactors, critical heat flux (CHF) under a counter-current flow limitation (CCFL) or a flooding condition are important to determine safety margins of fuel against CHF during a core flow reversal. The authors have proposed a CHF correlation scheme for the thermal hydraulic design of research reactors, based on CHF experiments for both upward and downward flows including CCFL condition. When the CHF correlation scheme was proposed, a subcooling effect for CHF correlation under CCFL condition had not been considered because of a conservative evaluation and a lack of enough CHF data to determine the subcooling effect on CHF. A too conservative evaluation is not appropriate for the design of research reactors because of construction costs etc. Also, conservativeness of the design must be determined precisely. In this study, therefore, the subcooling effect on CHF under the CCFL conditions in vertical rectangular channels heated from both sides were investigated quantitatively based on CHF experimental results obtained under uniform and nonuniform heat flux condition. As a result, it was made clear that CHF in this region increase linearly with an increase of the channel inlet subcooling and a new CHF correlation including the effect of channel inlet subcooling was proposed.

Enhancement of the transport critical current density in a YBaCuO ceramic by electron irradiation under remanent magnetic fields

Japanese Journal of Applied Physics, 35(6B), p.L766 - L769, 1996/06

https://doi.org/10.1143/JJAP.35.L766

no abstracts in English

Test results of the FER/ITER conductors in the FENIX test facility

Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Takahashi, Yoshikazu; Nishi, Masataka; Okuno, Kiyoshi; Yoshida, Kiyoshi; Nakajima, Hideo; Ando, Toshinari; Hosono, Fumikazu*; et al.

IEEE Transactions on Magnetics, 30(4), p.2042 - 2045, 1994/07

https://doi.org/10.1109/20.305669

no abstracts in English

Ion irradiation effects in EuBaCuO thin film

; Iwase, Akihiro; Iwata, Tadao; Maeta, Hiroshi; ;

J. Supercond., 7(1), p.241 - 242, 1994/00

no abstracts in English