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Central Solenoid (CSI and Toroidal Field (TF) model coils have been developed in order to establish technologies required to the ITER magnets. All of the development goals have been achieved, including the operation at 13 T, 46 kA and pulsed charging at 1.2 T/s in the CS model coil and the stable operation at 10 T, 80 kA under the ITER relevant stress condition in the TF model coil. Based on these results, further activities are now being performed, in extensive collaboration with industry, to optimize coil designs, to improve performances and to mitigate technical risks during the manufacture of the ITER magnets. One of the activities is to establish production capability of Nb3Sn strands having higher critical current density which was redesigned based on the detailed assessment of the conductor performance in the model coil experiments. Strands fulfilling the ITER requirement have successfully been obtained. Another set of activities are full scale manufacturing demonstrations on jacket material for CS and structural materials for TF coil. So far, large forged blocks of JJ1 and ST316LN and thick hot rolled plates of ST316LN were successfully produced as a trial fabrication for the TF coil structures. Experience in the TF model coil indicated a need to improve manufacturing processes for radial plate and a significant progress has also been obtained in this area. Achievements from these activities will provide a firm technical basis for ITER magnet construction including that for industry. [ABSTRACT FROM AUTHOR]

In the ITER superconducting magnets, the CIC conductors cooling is insured by supercritical helium forced flow in the central and annular parallel channels. In the Central Solenoid, with a thick square jacket conductor, the helium inlet is in the highest field region at the inner bore pancake joggle, and it has to support the high hoop force stress level with a very low stress concentration factor. In the TF magnets, a thin jacket circular conductor is wound in double pancakes, inserted into radial plates, stacked and embedded into a steel case. The helium inlets are located at the inner bore, in the limited space between the radial plates and the coil casing. The PF coils helium inlets, not studied here, are similar to the CS ones, but with a lower stress level. A complete qualification work on the CS and TF helium inlets is presented. A design optimization was performed, by FEM analysis, resulting in acceptable stress level for both helium inlets. The welding procedure was qualified and specific fatigue life mock-ups were designed, analyzed and manufactured using representative jacket materials. Fatigue life qualification at 4 K was performed in the FZK test facility applying the relevant loading and number of cycles. Hydraulic mock-ups were manufactured and qualified in the CEA test facility using GN2 at relevant Reynolds number. Pressure drop as well as flow repartition inside the conductors' petals were measured. The mechanical and hydraulic results are presented. [ABSTRACT FROM AUTHOR]

The ITER model coil experiments have revealed that degradation of the critical current (Ic) and n index occurred in large Nb3Sn CICC's and the larger the electromagnetic force, the larger was the degradation. However, such degradation was not observed in the Nb3Al CICC. The authors developed a new model, in which the degradation of the Ic and n index of an individual strand was taken into account, to interpret these results. Analytical model corrected from experimental results of a single strand is used in this model to estimate the degradation of each strand. The calculation results are in good agreement with the CICCs' test results. In addition, it is indicated that in case of the Nb3Sn CICC, the normal transition occurs from the strands at low field side in CICC cross section, where transverse load due to the electromagnetic force is the largest, resulting in the significant degradation in the Ic and the n index. In contrast, in the case of the Nb3Al CICC, the normal transition takes place from the strands at high field in the CICC cross section, where the transverse load is small, resulting in no degradation in the Ic and the n index. [ABSTRACT FROM AUTHOR]

Focuses on the development of an Nb3Sn conductor joint for the Central Solenoid (CS) Model Coil of the International Thermonuclear Experimental Reactor. Configuration of the butt joint for the CS Model Coil; Fabrication of hairpin cable; Joint resistance; Measurement of the quench current in various temperatures and fields.

Evaluates the performance of the coils made of Cable-In-Conduit Nb3Sn conductors for the Central Solenoid of the International Thermonuclear Experimental Reactor. Performance of fast ramp tests; Distribution of the current inside the cable; Measurement of the critical current; Determination of the fastest possible current ramps.

Focuses on the use of the pancake-wound technique in the development of the central solenoid (CS) coil of the Reduced Technical Objective/Reduced Cost for the International Thermonuclear Experimental Reactor. Coil design; Two alternatives for the CS conduit reinforcement; Assessment of the CS structure performance through an axisymmetric finite element method.

Describes the design and fabrication of an Central Solenoid Model Coil developed by the International Thermonuclear Experimental Reactor. Overview of the inner module fabrication; Peak field produced by the model coil; Coil winding procedure; Insulation technology and materials.

Reports on the completed fabrication of the Central Solenoid model coil's outer module developed by the International Thermonuclear Experimental Reactor. Eight layers consisting the outer module; Vacuum epoxy impregnation; Instrumentation; Criteria for the final inspection.

Describes the fabrication process involved in the Central Solenoid (CS) model coil program of the International Thermonuclear Experimental Reactor international collaboration and which was completed on May 1999. Fabrication of the CS insert coil; Helical winding; Terminal fabrication; Heat treatment procedure; Critical temperature test; Turn and ground insulation.