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Japan Atomic Energy Research Institute is constructing the International Thermonuclear Experimental Reactor common test facility for the Central Solenoid Model Coil which is around 180 tons, a forced-flow cooled magnet with the maximum pulsed operation of 2 T/s and generates the rated magnetic field of 13 T at 48 kA with stored energy of 668 MJ. The test facility consists of a coil vacuum chamber, a cryogenic system with the 5-kW refrigerator and 500-g/s cryogenic pump, two pairs of 50-kA current leads, two DC power supplies (50kA and 60kA) and two JT-60 pulsed power supplies (50 kA, [+ or -]4.5 kV and [+ or -]40 kA, [+ or -]1.5 kV). The facility will be demonstrating the refrigeration and operation of a fusion pulsed magnet and the design and construction will accumulate experience towards the construction of ITER.

The Engineering Design Activity (EDA) of International Thermonuclear Experimental Reactor (ITER) has been carried out since 1992 among the four Parties which are European Union, Japan, Russian Federation, and United States. The design and the fabrication of the Center Solenoid (CS) model coil is under way in the ITER-EDA. The CS model coil consists of four parts, which are the outer module, the inner module, insert, and the supporting structure. The design of the CS insert coil is reported and discussed. The inner diameter of the CS insert coil is 1.5m. The conductor of the CS insert coil is the same as that of the ITER-CS coil. The CS insert coil will be installed inside the CS model coil. The conductor performance will be demonstrated on the maximum magnetic flux density of 13 T at the test facility of Japan Atomic Energy Research Institute (JAERI).

Japan Atomic Energy Research Institute (JAERI) has been designing and developing the Central Solenoid (CS) model coil for International Thermonuclear Experimental Reactor (ITER). The CS model coil is composed of two modules and they will be manufactured by United States Home Team and Japanese Home Team. The coil winding method is two-conductors-in-hand and the coil which has an inner diameter of 1.6 m and an outer diameter of 3.6 m, produces a maximum field of 13 T. The coil will be tested in the JAERI facility. This paper describes the coil design, manufacturing procedure, stress analysis on the winding pack and AC loss analysis.

The [Nb.sub.3]Sn cable is being fabricated for the Central Solenoid (CS) Model Coil under the ITER Engineering-Design Activity. The cable consists of about 1000 strands whose diameter is 0.81 mm. The design current is 48 kA at a magnetic field of 13T. The 0.6-GJ CS model coil is operated in a pulse mode (0.5T/s). The first trial fabrication of a 100-m dummy cable and a 20-m superconducting cable was completed successfully. The second trial fabrication of a 1000-m dummy cable was performed to establish the stable manufacturing procedure in January, 1995. We measured the AC losses of the full-sized conductor and could determine the cable coupling time constant. We analyzed the heat generation of the CS model coil and calculated the temperature rise of the cable for the model coil.

Critical current of [Nb.sub.3]Al is less sensitive to strain than [Nb.sub.3]Sn. This characteristic makes a React-and-Wind method applicable in a large dimension coil. By applying the React-and-Wind method for Toloidal Field (TF) coil, technical difficulties in transfer of the conductor after reaction are eliminated and construction cost of magnet system can be reduced in comparison with a Wind-React-Insulate-Transfer method. Therefore, the [Nb.sub.3]Al conductor has large potential as candidate for the TF conductor. The experiment of a 60 kA-12.5T [Nb.sub.3]Al Insert is projected to demonstrate applicability of the React-and-Wind method with the [Nb.sub.3]Al conductor. The React-and-Wind method will be employed in the winding and 0.4% bending strain will be applied to the conductor. The major characteristics of the [Nb.sub.3]Al Insert are reported in this paper.

A 40-kA [Nb.sub.3]Al cable-in-conduit conductor has been developed for the toroidal field coils of fusion reactors, because [Nb.sub.3]Al has excellent mechanical performance. This conductor consists of 405 copper-stabilized multifilamentary strands inserted into a CuNi circular conduit. The [Nb.sub.3]Al strands are fabricated by the Jelly-roll process with a diameter of 1.22 mm. This conductor could be operated up to a current of 46 kA at an external field of 11.2 T. Accordingly, [Nb.sub.3]Al promises to soon become a useful superconductor for large-scale high-field applications, such as fusion machines.

The effect of cyclic pulsed operation on the coil performance was studied from the electrical and mechanical points of view in the second experiment of the [Nb.sub.3]Sn Demo Poloidal Coil (DPC-EX). Current sharing temperatures, ac losses, displacements, and strains were measured before and after cyclic pulsed operation, which consisted of about 350 cycles. No degradation of the electrical and mechanical performance of the DPC-EX was observed in the range of these cycles.

Japan Atomic Energy Research Institute (JAERI) has been developing 13-T, 40-kA conductors for the ITER Central Solenoid Scalable Model Coil. The conductors are composed of high performance [(NbTi).sub.3]Sn strands and titanium conduit. In this development work, 15-km length strand fabrication from a 100-kg billet, chrome plating, cabling of 675 or 768 strands, jacketing of titanium conduit, and so on were conducted by two mass production lines. In this paper, several test results are reported such as critical current measurements of full-scale conductors and AC loss measurements of sub-scale conductors.

The Japan Atomic Energy Research Institute (JAERI) has developed the Advanced Disk and the Hollow Monolithic conductors for the FER/ITER Toroidal Field coils. The Advanced Disk conductor is a Cable-in-Conduit conductor which consists of 324 Nb3Sn strands. The Hollow monolithic conductor has hollow cooling channels and 23 Nb3Sn strands. The JA-FENIX sample consists of a pair of straight legs: one leg is the Advanced disk conductor and another is the Hollow Monolithic one. The FENIX facility at the Lawrence Livermore National Laboratory (LLNL) can provide a magnetic field up to 13T on a sample conductor of over 40cm-length. The performance test of the JA-sample was carried out in Autumn 1992. The critical current, the current sharing temperature, and the stability margin of each conductor were measured in this test. These results are presented and discussed.