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An Nb3Al conductor with stainless steel (SS) conduit has been developed in the framework of ITER Engineering Design Activity. The critical current performance of this conductor was experimentally investigated by using a short conductor sample. The results show that the critical current achieves the expected, resulting in demonstrating the validity of the fabrication method. The thermal strain is generally applied to the strands if SS conduit is used because of the different thermal expansion between the strands and SS conduit. However, it was not applied in our sample, since the conductor length, a few meters, is too short to keep it by friction force between the cable and conduit. The thermal strain applied to the strands in a long conductor is therefore estimated by using the solid model, in which the strain on the strands and conduit are calculated from the equilibrium of their thermal forces, ignoring the effect of cabling on relaxation of the strain on the strands. The results indicate that the Nb3Al strands are subjected to a compressive thermal strain of less than 0.4%. The critical current degradation by this is less than 10%, even though the SS conduit is used. Consequently, its critical current is estimated to be 90kA, which is sufficiently high compared with the nominal, 46kA, at 13T and 4.5K. Furthermore, it should be noted that the large thermal force, 80kN, appears after the heat treatment at room temperature.

Central Solenoid (CS) model coil program is a backbone activity of International Thermonuclear Experimental Reactor (ITER) Engineering Design Activities (EDA). The CS model coil has been developed to demonstrate the ITER real CS coil by international collaborations. The first charge test of the CS model coil and CS insert coil was carried out from April to August 2000 success. It achieved 13T of the maximum magnetic flux density with DC and pulse operation. A performance test of the CS model coil and CS insert was done under relevant conditions of real ITER coils. The mechanical performance of the CS model coil and the CS insert coil is discussed. And the temperature rise during coil charge is also reported.

In the project for the International Thermonuclear Experimental Reactor (ITER), a Central Solenoid (CS) model coil was developed to demonstrate the feasibility of the coil design and fabrication procedure. The model coil was installed in the test facility at JAERI, Naka, and a performance test is being carried out. The cool-down was completed without cold He leakage at the beginning of April 2000. We could charge the model coil up to the nominal current of 46kA without quenching in the first DC charging test. The model coil could generate the maximum field of 13T, and the stored energy was 640MJ. A manual dump test was also performed with the time constant of 5.3s from the nominal current. A maximum voltage of 4.8kV appeared in the coil during the dump test, and no damage was found after the test. In the pulse operation test, the coil could be ramped up to the nominal current in 26s, with the maximum ramping rate of 0.5T/s. The target ramping rate of 0.4T/s was satisfied. The test results are described in this paper.