The European Union contributes around 20% of the cable-in-conduit conductor lengths needed for the ITER toroidal field (TF) magnet coils. For that purpose, 97 tons of Nb 3 Sn superconducting strand have been fabricated over five years, the production being completed in 2014. This superconducting strand has been manufactured by two companies, namely, Bruker EAS (Germany) and OST (USA), through the bronze route and the internal tin diffusion, respectively. This paper reports the outcomes of this strand mass production and of the strand characterization as performed by the suppliers and cross-checked on a regular basis by Durham University.

A significant effort is underway in the European Union for the manufacture of superconducting conductors for ITER TF and CS Model Coils. For the CSMC the EU will contribute about 6.5t of bronze Nb/sub 3/Sn strand, 1200 m of full size cable and the jacketing of the entire conductor length, 5787 m. The TFMC conductor, on the other hand, will be entirely manufactured within EU: 4t of internal tin Nb/sub 3/Sn strand, cabling and jacketing of 1 km of TF conductor. This paper deals with the present status of the industrial activities. The achievements and lessons learned from the various manufacturing processes are presented.

The main R&D task of the ITER programme is the manufacture of two Model Coils, a Central Solenoid (CS) and a Toroidal Field (TF) Model Coil. The European Union is currently putting a significant effort into the production of the Nb3Sn superconducting strands, full-size cable and jacketing for the conductors that will be used for the production of the two Model Coils. As far as the CS Model Coil is concerned, the contribution of the European Union consists in the production of 6.4 Tons of Nb3Sn strand, 1200 m of full-size cable and 5787 m of jacketing of the conductor. The TF conductor, on the other hand, will be completely manufactured in Europe with the production of 4 Tons of internal tin Nb3Sn strand and the cabling and jacketing of 1 Km of conductor. This paper presents the industrial activities developed and currently in progress for the realization of the different conductors.

The ITER model coils will use two types of strands, one with high Jc, HP I, one with low hysteretic losses, HP II. Main specifications for the two strands are: HP I: Jc (nonCu)>700 A/mm/sup 2/ at 12 T @ 4.2 K, hysteresis losses<600 mJ/cc (+-3 T); HP II: Jc (non Cu)>550 A/mm/sup 2/ at 12 T @ 4.2 K, hysteresis losses<200 mJ/cc (+-3 T). HP I strand performance is likely to be achieved by internal tin Nb/sub 3/Sn, HP II by a bronze route strand. About 25% of the 26 tonnes required by the model coils will be contributed by the European Community. The companies EM-LMI, Italy (for internal tin) and Vacuumschmelze, Germany (for bronze route) have been selected by ITER for the strand production. The achievement of HP II performance was already demonstrated by Vacuumschmelze on a 10 km strand manufactured for NET in the frame of a former contract. On the other hand, the HP I internal tin strand was to be developed. In view of this, a contract has been assigned to GEC Alsthom Intermagnetics, France, to have a back-up option for internal tin strand. EM-LMI (HP I strand) and Vacuumschmelze (HP II strand) have successfully manufactured Nb/sub 3/Sn multifilamentary wires complying with ITER specifications. Work is in progress at GEC Alsthom Intermagnetics to achieve HP I strand performances.<>

The work on YBa2Cu3O7 (1-2-3) at SIEMENS has established (i) processes for high quality (1-2-3) films on SrTiO3 or on ZrO2 by sputtering or laser evaporation respectively, (ii) a hypersonic spraying process to lay down (1-2-3) thick films on steel tubing, (iii) analytical tools for precise monitoring of the oxygen content in (1-2-3) and for the investigation of the defect structure on an atomic scale in films and bulk material, (iv) test wires of competitive but still moderate current densities, and (v) inductive test methods for homogeneity of films and procedures to form electrical contacts of low resistivity.