Research background(KSTAR, ITER)
Korea Superconducting Tokamak Advanced Research (KSTAR) project is to develop a steady-state capable advanced superconducting tokamak for establishing a scientific and technological basis for an attractive fusion reactor. Since the KSTAR mission includes the achievement of a steady-state-capable operation, the use of superconducting coils is an obvious choice for the magnet system. The KSTAR superconducting magnet system consists of 16 toroidal field (TF) and 14 poloidal field (PF) coils which include 8 central solenoid coils. Both the TF and PF coil systems use internally-cooled cable-in-conduit conductors (CICC). The TF coil system provides a magnetic field of 3.5 T at the plasma centre and the PF coil system provide a flux swing of 17 V s. The major achievement in the KSTAR magnet system development includes the development of CICC and the construction of a large scale superconducting magnet and the test facility. KSTAR TF and PF coils are successfully completed in the year 2007.
We were the main actors of the KSTAR magnets including magnet design and fabrication.
KSTAR magnet fabrication and test
The magnet system for ITER consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS), 6 Poloidal Field (PF) coils and 18 Correction Coils (CCs). All coils are superconducting. The TF generate the field to confine charged particles in the plasma, the CS provide the inductive flux to ramp up plasma current and contribute to plasma shaping, the PF provide the position equilibrium of plasma current and the plasma vertical stability. The CCs allow correction of error field harmonics due to position errors as well as from busbars and feeders.
We were responsible for the ITER PF coil fabrication as well as ITER TF conductor fabrication. The main constraint for the manufacturing for ITER coil was related to very large dimensions and complexity of design. A special technique therefore had to be required to manufacture such coils.
ITER TF Superconducting conductor including strand was developed.
Also, ITER PF coils are successfully manufactured, and the performance of the coils are demonstrated by the cold tests.
We have accumulated experiences and technology on how to fabricate ITER superconducting conductor and ITER superconducting magnets.