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Tani, Norio; Watanabe, Yasuhiro; Hotchi, Hideaki; Takayanagi, Tomohiro; Togashi, Tomohito; Horino, Koki
IEEE Transactions on Applied Superconductivity, 26(4), p.4101904_1 - 4101904_4, 2016/06
Field measurement was implemented in order to confirm performance of the pulse corrector quadrupole magnet (QDT) in the RCS. A result of the field measurement showed a 20% difference against the design value. We investigated the cause and made a study to restore the performance. We challenged a new approach to install shims on the pule magnet. Shims were produced with a laminating steel sheet. We found the permissible value by field calculation in as installation accuracy greatly depended on the performance. A shim has a sharp and long edge with a complicated shape. Therefore it was difficult to make a structure that can tolerate installation works. We made various trial manufactures and adopted a processing method with an adhesion steel sheet. The homogeneity of field became less than 1% by measurement and a QDT which laminated shims were installed showed a fully satisfactory performance. In this presentation I will report optimization of the pole shape and the result of the field measurement carried out afterward.
Sakurai, Takeru; Iguchi, Masahide; Nakahira, Masataka; Saito, Toru; Koizumi, Norikiyo
IEEE Transactions on Applied Superconductivity, 26(4), p.4204705_1 - 4204705_5, 2016/06
Japan Atomic Energy Agency (JAEA) has responsibility to procure 9 Toroidal Field (TF) coils and 19 TF coil structures for ITER project. A TF coil structure consists of the main body structure having D-shape with 13.6 m of height and 9 m of width in which a superconducting winding pack is enclosed and the components to connect adjacent TF coils or other surrounding components. TF coil structures are manufactured from austenitic stainless steel having high tensile strength and fracture toughness at cryogenic temperature (4K) in order to ensure the huge electromagnetic force. As structural materials, austenitic stainless steel having high Manganese and Nitrogen which was named as JJ1 and high Nitrogen containing 316LN stainless steel are applied. These materials are welded each other by Tungsten Inert Gas (TIG) welding with FMYJJ1, which had been developed for welding material based on JJ1. The cryogenic mechanical properties of welded joints which have over 200 mm of actual thickness are limited due to less demonstration of such a heavy thick joints. In addition, destructive test specimens cannot be taken from actual TF coil structure. Hence, it is necessary to confirm actual thickness of welded joint performance by actual welding conditions mock-up. JAEA manufactured some welded joint mock-ups having the same welding thickness and combination of base materials as actual TF coil structure by applying actual welding conditions. JAEA measured mechanical properties of tensile and fracture toughness in liquid Helium environment by using test specimens taken from these welded joint mock-ups. This study reports these mechanical test results of welded joints at cryogenic temperature. "The view and opinions expressed herein do not necessarily reflect those of the ITER Organization."
Tsuchiya, Katsuhiko; Murakami, Haruyuki; Kizu, Kaname; Koide, Yoshihiko; Yoshida, Kiyoshi
IEEE Transactions on Applied Superconductivity, 26(4), p.4202705_1 - 4202705_5, 2016/06
Times Cited Count：3 Percentile：19.02(Engineering, Electrical & Electronic)The programme of constructing JT-60SA tokamak is progressing under the framework of the Broader Approach project. JT-60SA has the superconducting magnet system has Poloidal field (PF) coils and Toroidal field (TF) coils. PF coil system, of which JAEA is in charge, has a central solenoid (CS) with four solenoid modules and six equilibrium field (EF) coils. A CS module has 549 turns of Nb
Sn superconducting conductor, and its scale is 2 m in diameter. EF coils, which are made of NbTi superconducting conductor, consist of the circular coils with various bores, ranging from 4.4 m to 12 m in diameter. Before real CS module was made, a model coil which consisted of a real size quad-pancake had been manufactured to check its performance at 5.5K. After it was confirmed, winding of real CS modules was started. Recently, all pancake coils of the first module of CS, CS1, was completed. CS1 will be tested at 5.5K just before completion. EF coils are manufactured at the on-site facility in JAEA Naka because these are too large to transport on the public road. Three EF coils, EF4, EF5 and EF6 were already completed and installed on the cryostat base in the torus hall in January 2014. These coils were manufactured with the great accuracy. Errors of current centre of the winding packs were within 0.6 mm (EF4 and EF5) and 1.3 mm (EF6) which were only 1/6 to 1/10 of the required tolerances. From summer in the last year, manufacturing of the remaining EF coils was started.
Ozeki, Hidemasa; Isono, Takaaki; Uno, Yasuhiro; Kawano, Katsumi; Kawasaki, Tsutomu; Ebisawa, Noboru; Okuno, Kiyoshi; Kido, Shuichi*; Semba, Tomoyuki*; Suzuki, Yozo*; et al.
IEEE Transactions on Applied Superconductivity, 26(4), p.4202504_1 - 4202504_4, 2016/06
Takayanagi, Tomohiro; Hayashi, Naoki; Kinsho, Michikazu; Ueno, Tomoaki*; Horino, Koki; Okabe, Kota; Irie, Yoshiro*
no journal, ,
New injection shift-bump (SB) power supply of the 3-GeV Rapid-Cycling Synchrotron (RCS) at Japan Proton Accelerator Research Complex (J-PARC) has been developed and manufactured. The power supply adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) at 32 kA peak by the Insulated Gate Bipolar transistor (IGBT) switch. However, in the test operation, the diodes of the DC charger for the capacitor in the Flat-top unit (Ft-unit) were frequently damaged. It is found the delay of the risetime for the current feedback loop is the cause of the overvoltage across the diodes. This paper reports the characteristic and troubleshooting of the SB power supply.
