The superconductivity group at the University of Twente has a technological breakthrough that is crucial for the success of tokamak fusion reactors. It is a very ingenious and robust superconducting cable. This makes for a very strong magnetic field that the energy generating very hot plasma constrains in the reactor core and thus lays the foundation for the fusion. The new cables heat up much less, so it is possibile to have significantly increased control of the plasma. Magnet coils are one third of the cost of a fusion power plant.
In the heart of the tokomak reactor nuclear fusion takes place in the plasma of 150 million degrees Celsius. To keep that unimaginably hot plasma in check is an extremely strong magnetic field (13 Tesla) is required, which can only be efficiently generated by superconductors.
The wrist-thick braid cables (six) rising 13 meters in the fusion reactor are composed of interwoven strands of 0.8 mm thick. First three of these thin wires bundled with two of superconducting niobiumtin and copper. This makes the whole copper resistant to heating and preventing an unwanted sudden termination of the superconducting state.