This is a cross section of the ITER test reactor (http://www.iter.org/doc/all/content/com/gallery/Media/7%20-%20Technical/In-cryostat%20Overview%20130116.jpg ...

At the same time, a large international group is busily constructing the massive ITER tokamak test reactor ... rare-earth barium copper oxide (ReBCO) magnet field coil, they made a big leap ...