ITER Completes Niobium-Tin Procurement

The ITER community is celebrating a significant milestone: the end of a nine-year campaign to procure 88 km of niobium-tin superconductor for ITER’s toroidal field coils. The total represents some 825 tons of material with an estimated market value of 350 million euros. Six ITER Members—China (7.5 percent), Europe (20.18 percent), Japan (25 percent), Korea (20.18 percent), Russia (19.3 percent) and the United States(8 percent)—participated in the process, ITER’s longest running procurement effort.

To meet ITER’s needs, production capacity had to be ramped up by one order of magnitude. In 2007, world production did not exceed 15 tons per year, as many considered niobium-tin a difficult material to work with due to the strain sensitivity of the niobium-tin superconducting strands.

In close association with the ITER Organization, the ITER members developed winding and jacketing facilities, launched qualification programs for processes and tooling and followed demanding process control and certification standards to ensure conformity with ITER’s technical specifications. Some 500 tons of copper and niobium-tin multifilament composite wires were produced for the toroidal field coils, then “bundled” to form cables and contained in a structural steel jacket. The ITER Organization qualified eight strand suppliers and four jacketing facilities during the global procurement effort.

The European ICAS consortium in Italy jacketed the last toroidal field conductor unit length in December 2016 from superconducting cable manufactured in the US and steel tubes sourced in Japan by the US Domestic Agency.

“This milestone represents the end of an amazing and challenging nine-year journey, which has been completed on time due to the good understanding and collaborative spirit between the partners,” says Arnaud Devred, head of the Superconductor Systems & Auxiliaries Section at ITER. “This procurement sums up much that is ITER—advanced technology, innovation, perseverance and strong international collaboration. For me, it’s an excellent illustration of how ITER is bringing people together.”

Arnaud says that technical issues encountered along the way were overcome by facing them head-on and working out pragmatic solutions together. “This spirit is expected to continue in the next phases of the toroidal field magnet procurement, as our European and Japanese partners produce the final coils.”