Nb3Sn strand is the basic building block of ITER’s large magnets, the key element that makes them superconducting. Superconductivity is essential to pursuing fusion energy generation because superconductors consume less power and are cheaper to operate than conventional counterparts, while carrying higher current and producing stronger magnetic field. Six Domestic Agencies (China, Europe, Japan, Korea, Russia and the US) are responsible for procuring over 400 tons of toroidal field conductor for ITER.
The Korean milestone was validated late November with the approval the Authorization To Proceed Points (ATPPs) by the ITER Organization for the final batch of strand billets. (A billet is the smallest traceable production unit of strand.) In order to assure quality and full traceability for ITER, the manufacturing information and test results of every billet are registered electronically in the Conductor Database, and then reviewed by the procuring Domestic Agency and finally given approval by the ITER Organization to proceed to next step. Remarkably, 2 038 individual Korean billets passed the thorough review by the Korean Domestic Agency and ITER.
The Korean share of toroidal field strand procurement amounts to 93 tons (20 percent of toroidal field strands). The manufacturing contract was awarded to Kiswire Advanced Technology (KAT), which began producing in 2009. To have completed the manufacturing in four years is an impressive rate of production considering that, worldwide, the production of Nb3Sn strand before ITER did not exceed 15 tons per year.
„The toroidal field conductor Procurement Arrangement with Korea is a good example of an ITER success story,” states Arnaud Devred, who is responsible for the Superconductor Systems & Auxiliaries at ITER. „The close collaboration of the Korean Domestic Agency and the ITER Organization to monitor execution enabled both parties to address production issues in a timely and effective manner. This milestone is all the more remarkable in that the strand supplier KAT was new to the business when the contract was launched, but managed to adapt to the world-class standards imposed by the Procurement Arrangement.”