Matsukawa, Makoto; Shimada, Katsuhiro; Yamauchi, Kunihito; Gaio, E.*; Ferro, A.*; Novello, L.*
Plasma Science and Technology, 15(3), p.257 - 260, 2013/03
To realize high performance plasmas in tokamak devices, error field correction (EFC) is one of the very important issues. Actually, error field correction coil is being planned in ITER using superconducting coils, while normal copper coils will be employed in JT-60SA. Similar coils are installed and under operation in many devices over the world. In the case of JT-60SA, EFC coils will be realized by 12 (or 18) sector coils installed inside the vacuum vessel. This paper describes a conceptual design study for the circuit configuration and control strategy of the power supply system of these EFC coils. In conclusion, to minimize the number of current feeders and semiconductor power devices, multi-phase inverter is the best solution not only from the cost merit but also from a view point of canceling the induced voltage of axisymmetric magnetic component.
Someya, Yoji; Tobita, Kenji
Plasma Science and Technology, 15(2), p.171 - 174, 2013/02
When one wants to simply estimate Tritium Breeding Ratio (TBR) using 1D analysis, the TBR may be reduced from a "local" TBR for the breeding zone of a blanket module by multiplying the breeder coverage. The gap between adjoining modules and the frames of the modules are regarded as non-breeding zones. Based on the methodology, the width of the blanket modules gap was determined to be 5 mm or less in the SlimCS DEMO reactor. Contrary to this, recent study revealed that neutrons scattered in the non-breeding zones can enter breeding zones, contributing to tritium production. This means that the estimation method mentioned above tends to underestimate TBR. In order to assess the scattering effect quantitatively, we carried out the 3D Monte Carlo code MCNP-5 calculation. When a values of the TBR compare the MCNP to the previous method, indicating little decrease in TBR for the gap of less than 2 cm. The allowance of the gap will facilitate access of remote handling systems for replacement of the blanket modules.
Shimada, Katsuhiro; Terakado, Tsunehisa; Yamauchi, Kunihito; Matsukawa, Makoto; Baulaigue, O.*; Coletti, R.*; Coletti, A.*; Novello, L.*
Plasma Science and Technology, 15(2), p.184 - 187, 2013/02
Nakamura, Shigetoshi; Shibama, Yusuke; Masaki, Kei; Sakasai, Akira
Plasma Science and Technology, 15(2), p.188 - 191, 2013/02
The JT-60SA project is to contribute to realization of fusion energy by supporting exploitation of ITER and by complementing ITER and engineering issues for DEMO reactors. A main component providing vacuum insulation, radiation shield, and tokamak machine components' support, is cryostat. We present integrity of top lid of the cryostat, which is final part to close a cryostat vessel. We calculate clamp structural parameters, which are weight, dimension, and stiffness, required to fasten a top flange of the top lid with a body flange of the cryostat vessel. To achieve vacuum insulation of 10 Pa, the top flange and the body flange are lightly welded. Under vacuum condition, tensile load is loaded to the weld by bending deformation of the top flange. Bending moment is loaded to the weld by radial component of the deformation. The weld needs clamp structure to reduce these loads. We present integrity of the top lid with clamp.
Yamauchi, Kunihito; Shimada, Katsuhiro; Terakado, Tsunehisa; Matsukawa, Makoto; Coletti, R.*; Lampasi, A.*; Gaio, E.*; Coletti, A.*; Novello, L.*
Plasma Science and Technology, 15(2), p.148 - 151, 2013/02
Tobari, Hiroyuki; Taniguchi, Masaki; Kashiwagi, Mieko; Dairaku, Masayuki; Umeda, Naotaka; Yamanaka, Haruhiko; Tsuchida, Kazuki; Takemoto, Jumpei; Watanabe, Kazuhiro; Inoue, Takashi; et al.
Plasma Science and Technology, 15(2), p.179 - 183, 2013/02
Vacuum insulation is a common issue for the accelerator and the HV bushing for the ITER NBI. The HV bushing has five-stage structure and each stage consists of double-layered insulators. Hence, several triple points exist around the insulators. To reduce electric field at those points simultaneously, three types of stress ring were developed. In voltage holding test of a full-scale mockup equipped with those stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, voltage holding capability was not sufficient due to breakdown triggered by electric field concentration at edge and corner on grid components. By extending gap length, 1 MV was sustained in vacuum. Furthermore, with new accelerator grids which compensates beam deflection due to magnetic field and space charge repulsion between beamlets, 980 keV, 185 A/m H ion beam acceleration was demonstrated, which was close to ITER requirement.
Koizumi, Norikiyo; Nakajima, Hideo
no journal, ,
The ITER superconducting magnet system consists of 18 TF coils, 1 CS, 6 PF coils and 18 Correction coils. The TF conductors will be manufactured by China (7%), EU (20%), Korea (20%), Japan (25%), Russia (20%) and US (8%), TF coils by EU (10 coils) and Japan (9 coils), in which one spare is included, all TF coil cases by Japan, all CS conductors by Japan, all CS (7 modules including a spare), PF conductor by China (65%), EU (21%) and Russia (14%), PF coils by EU (5 coils) and Russia (1 coil), all Correction coils by China and all feeder by China, respectively. Since the TF coil manufacture is one of long-lead items, the procurement of the TF conductors have been started. More than 15 TF conductors have already been fabricated in Japan and dummy conductors were manufactured by China and Russia. Large-scale trials for TF coil manufacture have also been started and successful results were obtained in both EU and Japan Domestic Agencies.
Ide, Shunsuke; JT-60SA Team
no journal, ,
no journal, ,