Charging test results of the DPC-TJ, a high-current-density large superconducting coil for fusion machines

The authors describe the electromagnetic results and the quench phenomena of the DPC-TJ large cable-in-conduit Nb/sub 3/Sn coil experiment which took place in the summer of 1991. The DPC-TJ coil was developed by Toshiba and JAERI in collaboration to demonstrate the realization of (NbTi)/sub 3/Sn superconducting coils for fusion with high average current density of 40 A/mm/sup 2/. The coil was charged up to its rated current of 24 kA (40 A/mm/sup 2/) at 7.6 T without quench in the DPC test facility. Thereafter, the electromagnetic performance was tested by measuring I/sub c/ and T/sub cs/, and the critical current at 12 T was estimated to be 41 kA. The quench phenomena of the DPC-TJ coil were also tested by measuring normal-zone propagation velocity to get the protection design. In these experiments, very slow and very fast propagation were observed. Many other electromagnetic results were also obtained, which are necessary for the design of fusion machines such as International Thermonuclear Experimental Reactor. >