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The support structure of the TF coils is designed to withstand the larger electromagnetic force on the basis of the stress analyses. The maximum displacement and the Tresca stress of the TF coil are evaluated in the cas4e of the plasma disruption at the end of plasma current flat-top.

The internal resonance phenomenon of a large-scale superconducting coil is described. The frequency dependence of the electric impedance defined at the coil terminal and the voltage distribution of the layer winding are measured at the ITER CS model coil under the superconducting state in advance of the pulse operation test.

Pulse operation testing of the ITER CS model coil was undertaken using the JT-60 power supply system.

This paper describes the internal resonance phenomenon of a large scale superconducting coil. The frequency dependence of electric impedance defined at the coil terminal and the voltage distribution of the layer winding were measured at the ITER CS model coil under the superconducting state in advance of the pulse operation test. As a result, large change of the impedance and unbalance of the layer voltage were observed. The AC circuit analysis was carried out in order to evaluate the measurement results and to calculate the voltage of layer insulator. It was concluded that the higher voltage, which may appear on the layer insulation, is about a half of the coil terminal voltage in high frequency. [ABSTRACT FROM AUTHOR]

The modification of JT-60 was programmed to be a superconducting tokamak (JT-60SC) that has superconducting toroidal field (TF) and poloidal field coils. The Nb3Al superconductor was developed in order to apply to the TF coil system in JT-60SC. The TF coil conductor was designed with a cable-in-conduit (CIC) type. This conductor was Nb3Al cable jacketed into stainless steel (SS) conduit. As the first step of SS conduit production, the 10 m long round-in-square type tubes were successfully fabricated within eccentricity tolerance of the tube hole (<10%). A 30 m SS conduit was made of three units of 10 m long tubes, which were butt-welded in series. After the welding process, penetrating beads were observed by CCD camera, and it was visually clear that the penetrating beads were successfully controlled by adjustment of back-shielding gas pressure. Therefore, regarding the production of SS conduit, the procedures of fabrication and inspection were established. Then, the inserting of cable into this conduit and compaction were also carried out. Consequently, the 30 m Nb3Al CIC conductor was successfully fabricated, so that a feasibility of mass-producing CIC conductor applied to the real machine was obtained. [Copyright &y& Elsevier]