Natsume, Kyohei; Murakami, Haruyuki; Kizu, Kaname; Yoshida, Kiyoshi; Koide, Yoshihiko
IOP Conference Series; Materials Science and Engineering, 101(1), p.012113_1 - 012113_8, 2015/12
Obana, Tetsuhiro*; Murakami, Haruyuki; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Natsume, Kyohei; Yoshida, Kiyoshi
Physica C, 518, p.96 - 100, 2015/11
Kizu, Kaname; Murakami, Haruyuki; Natsume, Kyohei; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*
Fusion Engineering and Design, 98-99, p.1094 - 1097, 2015/10
Current feeder and Coil Terminal Box (CTB) for the superconducting magnets for JT-60SA were designed. Copper busbar from power supply is connected to the High Temperature Superconductor Current Lead (HTS CL), which is installed on the vacuum vessel called CTB. The superconducting current feeder is connected to the cold end of HTS CL, and is led to main cryostat for magnets. Trial manufacturing of crank shaped feeder to reduce the thermal stress was performed. The small tool which can connect soldering joint with vertical direction was developed. Insulation materials made by manufacturing condition showed sufficient shear stress. Since the all manufacturing process concerned was confirmed, the production of current feeder and CTB can be started.
Koide, Yoshihiko; Yoshida, Kiyoshi; Wanner, M.*; Barabaschi, P.*; Cucchiaro, A.*; Davis, S.*; Decool, P.*; Di Pietro, E.*; Disset, G.*; Genini, L.*; et al.
Nuclear Fusion, 55(8), p.086001_1 - 086001_7, 2015/08
The most distinctive feature of the superconducting magnet system for JT-60SA is the optimized coil structure in terms of the space utilization as well as the highly accurate coil manufacturing, thus meeting the requirements for the steady-state tokamak research: A conceptually new outer inter-coil structure separated from the casing is introduced to the toroidal field coils to realize their slender shape, allowing large-bore diagnostic ports for detailed plasma measurements. A method to minimize the manufacturing error of the equilibrium-field coils has been established, aiming at the precise plasma shape/position control. A compact butt-joint has been successfully developed for the Central Solenoid, which allows an optimized utilization of the limited space for the Central Solenoid to extend the duration of the plasma pulse.
Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Furukawa, Masato; Natsume, Kyohei; Tsuchiya, Katsuhiko; Kamiya, Koji; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4201305_1 - 4201305_5, 2015/06
JT-60U magnet system will be upgraded to the superconducting coils in the JT-60SA programme of the Broader Approach activities. Terminal joint of Central Solenoid (CS) is wrap type NbSn-NbTi joint used for connecting CS (NbSn) and current feeder (NbTi). The terminal joints are placed at the top and the bottom of the CS systems. CS modules located at middle position of CS system need the lead extension from the modules to the terminal joint. The joint resistance measurement of terminal joint was performed in the test facility of National Institute for Fusion Science. The joint resistance was evaluated by the operating current and the voltage between both ends of the terminal joint part. Test results met the requirement of JT-60SA magnet system. The structural analysis of the lead extension and its support structure was conducted to confirm the support design. In this paper, the results of resistance test of joint and the structural analysis results of lead extension are reported.
Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi
Fusion Engineering and Design, 90, p.55 - 61, 2015/01
In the cold test of the JT-60SA CS model coil made by NbSn CIC conductor, magnetic fields were measured using Hall sensors. While holding coil current of 20 kA, the magnetic fields were varying slightly with several long time constants. The range of the time constant was from 17 sec to 571 sec, which was much longer than the time constant derived from the measurement using the short straight sample. To validate the measurements, the magnetic fields of the model coil were calculated using the calculation model representing the positions of NbSn strands inside the CIC conductor. The calculations were in good agreement with the measurements. Consequently, the validity of magnetic field measurements was confirmed.
Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Natsume, Kyohei*; Imagawa, Shinsaku*; Mito, Toshiyuki*; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi
Plasma and Fusion Research (Internet), 9(Sp.2), p.3405122_1 - 3405122_4, 2014/07
To evaluate the fabrication technology of the butt joint composed of NbSn CIC conductors, joint resistance and quench current were measured using a sample developed for the JT-60SA CS coil. The measurements indicate that the butt joint fulfilled the design requirements. To simulate the characteristics of the butt joint, one dimensional numerical model simplifying the butt joint configuration was developed. Using the model, joint resistance and quench current of the butt joint were calculated. The calculations were in good agreement with the measurements. As a result, the model will be valid for the simulation of the butt joint.
Yoshida, Kiyoshi; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Kamiya, Koji; Koide, Yoshihiko; Phillips, G.*; Zani, L.*; Wanner, M.*; Barabaschi, P.*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4200806_1 - 4200806_6, 2014/06
The upgrade of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by Japan and EU in the BA agreement. All components of magnet system are now under manufacturing in mass production. The first superconducting EF conductor was manufactured in 2010 in Japan. First superconducting coil EF4 was manufactured in 2012. Other EF5 and EF6 coils shall be manufactured by 2013 to install temporally on the cryostat base before the assembly of the plasma vacuum vessel. CS model coil is fabricated to qualify all manufacturing process of NbSn conductor. The first TF conductor was manufactured in 2012. The cryogenic requirements for JT-60SA are about 9 kW at 4.5K. Each coil is connected through an in-cryostat feeder to the current leads located outside the cryostat in the CTB. A total of 26 HTS current leads are installed in the CTB. The manufacturing of the magnet system is in progress to provide components to assembly the Tokamak machine.
Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Natsume, Kyohei*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4200205_1 - 4200205_5, 2014/06
Central Solenoid (CS) of JT-60SA are designed with the NbSn cable in conduit conductor. CS model coil (CSMC) was manufactured by using the real manufacturing jigs and procedure to validate the CS manufacturing processes before starting mass production. The dimensions of the CSMC are the same as real quad-pancake. The cold test of the CSMC was performed and the test results satisfied the design requirements. These results indicate that the manufacturing processes of the JT-60SA CS has been established. In this paper, the development and the validation of the CS manufacturing processes are described.
Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Yoshizawa, Norio; Koide, Yoshihiko; Yoshida, Kiyoshi
IEEE Transactions on Plasma Science, 42(4), p.1042 - 1046, 2014/04
JT-60SA is full superconducting tokamak that was constructed in JAEA Naka site in corporation with JAEA and F4E. The central solenoid (CS) assembly in JT-60SA consists of 4 modules of superconducting solenoid which has outer diameter of 2m and height of 1.6m. The currents for each module were independently controlled. CS was designed to produce enough flux to control the plasmas with 5.5 MA during 100 sec. Superconducting conductor for CS consists of NbSn strands. The support structure for CS assembly consists of the tie-plates (inner and outer), buffer zones and key-blocks. CS must be cooled down to 4K before charging, and modules will be shrunk during this process. The support structure made of stainless steel was also shrunk at 4K. Thermal expansion ratio of stainless steel, however, is different from that of modules, which would result in the gap between modules and supports. In order to cancel this gap, pre-compress mechanism needs to be introduced in the support structure for CS assembly. Mechanical pressure for the pre-compress will be controlled by hydraulic rams that are set at the top of each support. During the pre-compress process in which both key-blocks clamp the modules, tension works at the tie plates. The support structure for CS assembly, especially tie plates, should have sufficient mechanical strength to withstand the stress induced by the pre-compress at room temperature, not only to withstand the electro-magnetic force which was produced during the plasma operation. Space for installation of CS assembly is limited by TF coils, so that cross section of tie-plate is also limited. Final structure was successfully designed to adopt the stainless steel with 0.120.17 wt% of nitrogen content (SS316LN) for the material of the main parts of support structure.
Kamiya, Koji; Furukawa, Masato; Hatakenaka, Ryuta*; Miyakita, Takeshi*; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi
AIP Conference Proceedings 1573, p.455 - 462, 2014/01
The thermal shield of JT-60SA is kept at 80 K and will use the Multi Layered Insulator (MLI) to reduce radiation heat load to the superconducting coils at 4.4 K from the cryostat at 300 K. Due to plasma pulse operation, the MLI is affected by eddy current in toroidal direction. The MLI is designed to suppress the current by electrically insulating every 20 degree in the toroidal direction by covering the MLI with polyimide films. In this paper, two kinds of designs for insulated MLI are proposed focusing on a way to overlap MLI. A boil-off calorimeter method and temperature measurement has been performed to determine the thermal performance of MLI. The design of electrical insulated thermal anchor between the toroidal field (TF) coil and the thermal shield is also explained.
Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi
Fusion Engineering and Design, 88(11), p.2773 - 2776, 2013/11
To evaluate joint fabrication technology, resistance measurements were conducted using a sample consisting of pancake and terminal joints for the JT-60SA EF coils. Both joints fulfilled the design requirement of 5 at the external field of 3 T. The electrical resistance of the pancake joint was slightly lower than that of the terminal joint. Analyses indicated that the characteristics of the conductors used in the joints affect those of the joints. The presence or absence of copper wires in the conductor is one factor that determines the characteristics of the joints.
Yoshida, Kiyoshi; Kizu, Kaname; Murakami, Haruyuki; Kamiya, Koji; Honda, Atsushi; Onishi, Yoshihiro; Furukawa, Masato; Asakawa, Shuji; Kuramochi, Masaya; Kurihara, Kenichi
Fusion Engineering and Design, 88(9-10), p.1499 - 1504, 2013/10
The modifying of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by both parties of Japanese government and European commission (EU) in the Broader Approach agreement. The magnet system for JT-60SA consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules, and 6 Equilibrium Field (EF) coils. The manufacturing of the JT-60SA magnet system is in progress in EU and Japan. The JT-60SA superconducting magnet system generates an average heat load of 3.2 kW at 4 K to the cryoplant, from nuclear and thermal radiation, conduction and electromagnetic heating, and requires current supplies 20 kA for 4 CS modules and 6 EF coils, 25.7 kA to 18 TF coils. The helium flow to remove this heat, consisting of supercritical helium at pressures up to 0.5 MPa and temperature between 4.4-4.8 K, is distributed to the coils and structures through the valve box (VB) from the cryoline connecting to the auxiliary cold box located outside the torus hall. The feeders also contain the electrical supplies from the current lead transitions to room temperature to the coil. The feeder components consist of the in-cryostat feeders with flexible parts to allow coil operational displacements from the connection pipes out of the cryostat, including S-bend conductor to allow differential thermal contraction and the coil terminal boxes (CTBs) with HIS current leads. A measurement and control system is required to monitor and control these coils and feeders for safety and optimal operational availability. For each coil, both current and supercritical helium are supplied from external systems and are controlled from a central system as part of the regular operation with plasma pulses. Quench detection instruments for superconducting coils, feeders and HTS current leads are provided as a separate, stand alone system.
Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Kashiwa, Yoshitoshi; Yoshizawa, Norio; Yoshida, Kiyoshi; Hasegawa, Mitsuru*; Kuno, Kazuo*; Nomoto, Kazuhiro*; Horii, Hiroyuki*
Fusion Engineering and Design, 88(6-8), p.551 - 554, 2013/10
The programme of constructing JT-60SA device is progressing under the framework of the Broader Approach project. Superconducting poloidal field (PF) coil system, which was decided to be procured by Japan, consists of a central solenoid (CS) with four solenoid modules and six equilibrium field (EF) coils. Each of EF coil has individual diameters, 4.5 to 12 m. Fabrication of EF4 coil, which is set at the lowermost of torus, was started from the beginning of 2009 as a first EF coil. EF4 coil has ten double pancake (DP) coils, and sizes of circularity were measured for all DP coil after curing process. Maximum error of circularity was 3.1 mm, which was nearly a half of the design tolerance, 6 mm. After stacking these DP coils, winding pack of EF4 was completed in the spring of 2012. After optimizing the positions of DP coils to cancel the error of circulation which each DP coil has, error of radial current centre of DP coils will be achieved in the range between + 0.2 to - 0.4 mm. Structural analysis of terminal structure was also performed. Terminal part has a pair of conductors bended toward the lower side of winding pack. A side of them (positive terminal) was covered by stainless steel armor to prevent the movement by electromagnetic force because a length of conductor was longer due to starting from the top of winding pack. Another side (negative terminal) was not covered by armor in the first design because this length was relatively short. However, it was clear on the structural analysis that mechanical strength of insulation around this terminal was not sufficient. Therefore, we also reinforced this side with stainless steel. From this April, fabrication of EF coils with large bore (larger than 8 m of diameter) will be started at the facility built in JAEA Naka site. In this paper, we will discuss about technological problem during the fabrication of large bore EF coils, such as temperature control at the winding process.
Kizu, Kaname; Murakami, Haruyuki; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Nomoto, Kazuhiro*; Imai, Yoshio*; Minato, Tsuneaki*; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*
IEEE Transactions on Applied Superconductivity, 23(3), p.4200104_1 - 4200104_4, 2013/06
The maximum magnetic field, current and voltage of CS for JT-60SA are 8.9 T, 20 kA and 10 kV, respectively. NbSn conductor with high field and high current density was developed. The outer diameter and height of CS are 2 and 1.6 m, respectively. Several components were newly developed and tested. To increase the supplying flux, winding diameter should be maximized as possible. The butt type joint was developed that can minimize the joint space. DGEBA epoxy used for main binder of insulation showed sufficient tensile strength even though the ray irradiation of 100 kGy. Insulation characteristics of 44 stack sample applying double of operational stress with operational cycle showed the larger withstand voltage than 21 kV. According to these results, the fabrication of CS can be started.
Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Yamauchi, Kunihito; Shimada, Katsuhiro; Terakado, Tsunehisa; Matsukawa, Makoto; Hasegawa, Mitsuru*; Minato, Tsuneaki*; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.9501405_1 - 9501405_5, 2012/06
The withstand voltage of turn insulation is essential issues for the superconducting magnet. The actual turn voltage is larger than the turn voltage under the ideal condition because of the voltage fluctuations of the power supply and the resonance phenomenon in the magnet. In this paper, the voltage measurement of the JT-60U power supply and the resonance characteristics of the EF4 are described. The actual maximum turn voltage is almost same as the voltage under the ideal condition.
Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi; Kurihara, Kenichi; Hasegawa, Mitsuru*; Kuno, Kazuo*; Nomoto, Kazuhiro*; Horii, Hiroyuki*
IEEE Transactions on Applied Superconductivity, 22(3), p.4202304_1 - 4202304_4, 2012/06
no abstracts in English
Yoshida, Kiyoshi; Kizu, Kaname; Tsuchiya, Katsuhiko; Murakami, Haruyuki; Kamiya, Koji; Payrot, M.*; Zani, L.*; Wanner, M.*; Barabaschi, P.*; Heller, R.*; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.4200304_1 - 4200304_4, 2012/06
The JT-60SA is progressing as a "satellite" facility for ITER in the Broader Approach agreement. The fabrications of the conductor for CS and EF coils were started in 2008. The first superconducting conductor of EF4 coil was manufactured at March 2010. The manufacturing tools for EF coils are design and prepared from 2009. The double pancake using the superconductor has been started at 2011. The TF coil case encloses the winding pack and is the main structural component of the magnet system. The interface between TF case and CS and EF coil were designed. The conductor for TF coils fabrication has been started. The cryogenic system is equivalent to be about 9 kW refrigeration at 4.5 K. Each coil is electrically connected through the in-cryostat feeder and the coil terminal boxes. The 26 current leads using high temperature superconductor. The manufacturing of superconducting magnet for JT-60SA are started by solving its cost and technology.
Kamiya, Koji; Onishi, Yoshihiro; Ichige, Toshikatsu; Furukawa, Masato; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Mizumaki, Shoichi*
Proceedings of 24th International Cryogenic Engineering Conference (ICEC 24) and International Cryogenic Materials Conference 2012 (ICMC 2012) (CD-ROM), p.587 - 590, 2012/05
The JT-60 plans to be upgraded to a full-superconducting tokamak referred as the JT-60 Super Advance (JT-60SA) as one of the JA-EU broader approach projects. In the JT-60SA, the superconducting magnets are surrounded by thermal shield cooled at 80 K, which is categorized into 3 groups; the vacuum vessel thermal shield (VVTS), the port thermal shield (PTS) and the cryostat thermal shield (CTS). In this study, seismic analysis was conducted for the thermal shield to confirm the soundness of the latest design, taking the dynamical analysis into account. Trial manufacturing of a 10 degree outer VVTS was also conducted. The outer VVTS was subsequently assembled with already existing inner VVTS to measure the total tolerance (manufacturing plus assembly). It was found that the total tolerance was 5.2 mm which is less than the target tolerance of 10 mm. Finally, concept and the current status of the JT-60SA cryodistribution design are reported.
Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Kamiya, Koji; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*; Yanagi, Nagato*; et al.
Proceedings of 24th International Cryogenic Engineering Conference (ICEC 24) and International Cryogenic Materials Conference 2012 (ICMC 2012) (CD-ROM), p.575 - 578, 2012/05
The JT-60U magnet system will be upgraded to the superconducting coils (JT-60SA) in the Broader Approach (BA) project. The JT-60SA magnet system has 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules and 6 Equilibrium Field (EF) coils. The CS conductors are designed with NbSn cable in conduit (CIC) conductor because the magnetic field of CS is up to 8.9 T. The short CS conductor was manufactured and processed into the performance verification test sample. The Tcs test results indicate that the initial Tcs of the CS conductor is about 2 K higher than the minimum requirement of the conductor design. In addition the Tcs after the repetition excitation is more important issues for the CS conductor because the CS conductor is made of NbSn strand. The Tcs changes with the repetition excitation and the influence of the warm up and cool down process on the Tcs were measured. The test results show that there is no degradation while the repetition excitation tests. The AC loss test of the CS conductor was also performed for precise estimation of the conductor heat loads. The Tcs margin analysis of the CS conductor was conducted based on the latest conductor heat loads. The analysis results show that the CS conductor has enough Tcs margin during the JT-60SA operation. These results show that the design and the manufacturing process of the CS conductor satisfy its requirements. Thus CS conductors for the CS1 module have been manufactured on the mass production process. In this paper, the Tcs test, the repetition excitation test, the AC loss test and the Tcs margin analysis of the CS conductor are described.