During May 6. – 9. 2003 a meeting to review the achievements in the ITER magnet research & development (R&D) programme over the last 10 years was held at EFDA CSU Garching (Germany). Representatives from the ITER-International Team (IT), and the Participating Teams from Europe, Japan, Russian Federation and the United States were welcomed. Dr. M. Huguet, head of the ITER site at Naka (Japan) and Dr. E. Salpietro from EFDA CSU Garching (Germany) co-chaired the sessions. The results from the ITER magnet R&D programme, including the manufacture and test of two model coils and three conductor inserts, have now been evaluated. The following subjects were covered during the meeting:

• The results from the model coil tests
• Improved design of the Toroidal Field and Central Solenoid conductor
• Advances in Nb3Sn strand production and quality
• The Toroidal Field jacket material and conductor
• The Central Solenoid jacket material and conductor.

The primary goal of the meeting was to converge on the optimal conductor designs for the Toroidal Field and Central Solenoid coils. The main activity in the magnet R&D has been the manufacture and testing of the Central Solenoid and the Toroidal Field model coils.The Central Solenoid Model Coil was a joint effort between Japan, the European Union, the Russian Federation and the US, and was installed in the JAERI Naka facility (Japan). The Toroidal Field Model Coil was entirely built by the European Union and tested at Forschungszentrum Karlsruhe (Germany) with the participation of other ITER partners. Both projects (referred to as L1 for Central Solenoid and L2 for Toroidal Field) have demonstrated that the Nb3Sn technology required to manufacture the coils for ITER has been successfully developed.

Three conductor insert coils have also been tested in Naka, using the Central Solenoid Model Coil to produce a background field, and a fourth insert is on its way. The first insert simulated the Central Solenoid conductor (Japan / US project), the second was a Nb3AI conductor insert (Japan) and the third a Toroidal Field conductor in titanium jacket (Russian Federation). The fourth, for which tests are scheduled for 2004, will be a NbTi Poloidal Field conductor insert (European Union / Russian Federation project).

The successful tests of both Model Coils and inserts have confirmed the original design and given further insight on how to enhance the performance of the conductors towards higher operational margins. The ITER IT, taking advantage of the lessons learned from the R&D programme, presented a variety of options for the optimization of the performance of the conductors by using higher performance strands and different jacket materials.

After assessing the results, it was concluded that the preferred design solution for the conductors of both the Toroidal Field Coils and the Central Solenoid should be based on high performance strand with a stainless steel jacket.

High priority R&D items to optimize the conductors for ITER:
- Quantifying the impact of transverse load on strand and on the conductor performance
- Control of strand cost