The Central Solenoid (CS) model coil programme was performed since 1992 as one of the projects in the Engineering Design Activity (EDA) of the International Thermonuclear Experimental Reactor (ITER). The CS model coil programme involves a plan to develop the Toroidal Filed (TF) insert to demonstrate the conductor performance of ITER TF coils under a magnetic flux density of 13T. The TF insert was fabricated by Russia and tested by Japan under the framework of the ITER-EDA. The TF insert developed a single-layer solenoid with nine turns. It is wound with a cable-in-conduit (CIC) conductor which consists of 1, 152 Nb3Sn strands, a thin titanium jacket and a central channel. The outer diameter, height and weight of the TF insert are 1.56m, 3.2m and 3.1ton, respectively. Fabrication of the TF insert was completed in May 2001 at the D. V. Efremov Scientific Research Institute for Electrophysical Apparatus (Efremov institute) in St. Petersburg, Russia. The TF insert was then transported to the Japan Atomic Energy Research Institute (JAERI). Installation of the TF insert to CS model coil test facility was completed in August, 2001. Experiments including the cooldown and warmup processes, were completed in November 2001. The TF insert was charged to 13T with 46kA without any instability under a back up magnetic field from the CS model coil. This report introduces an overview of the fabrication, installation and experiments for the TF insert conducted under collaboration between Japan and Russia.
The Central Solenoid (CS) model coil program was established in 1992 as one of projects in the Engineering Design Activities (EDA) of the International Thermonuclear Experimental Reacter (ITER). Current sharing temperature (Tcs) measurement of an ITER toroidal field insert (TF insert) was performed. The coil is a Nb3Sn superconducting coil, and was installed inside of the ITER CS model coil as a backup field coil. The relation between the voltage of an individual strand composed of the TF insert conductor and the measured voltage using the taps on the jacket were investigated, and evaluation method for Tcs measurement was established. The obtained results show that there was a discrepancy between the expected value from the strand data and the measured value, which is lower by about 1.2K. Some discrepancy was observed just after cooling down the insert before energizing.
The Central Solenoid (CS) model coil program was established in 1992 as one of projects for the Engineering Design Activities of the International Thermonuclear Experimental Reactor (ITER) and has been an ongoing activity ever since. A CS model coil and a Toroidal Field (TF) Insert have been developed and tested successfully. The TF insert is comprised of a cable-in-conduit conductor that consists of 1, 152 superconducting strands bundled on a central cooling channel. An experiment was conducted to investigate the pressure drop performance of the TF insert. There were two purposes for the investigation: one to verify pressure drop prediction using correlations proposed by various researchers, and other to investigate the behavior of the pressure drop under electromagnetic forces. The pressure drop of the TF insert decreased by approximately 12% during current-carrying operation of 46kA at 13T. After several current-carrying operations, the friction factor of the TF insert finally reached a value that was approximately 10% lower than that of original state and was not recovered even without current. It is believed that the cable cross-section inside the conductor jacket became deformed due to electromagnetic force and a new flow path in the jacket was generated.