The most powerful pulsed superconducting magnet system ever built is complete and will soon become part of the world’s most ambitious energy experiment.
The system is the central electromagnet of the International Thermonuclear Experimental Reactor (ITER), a tall magnetic core built and tested in the United States and destined for southern France, where the giant tokamak is being assembled as part of an international project. The magnetic system will serve as the electromagnetic “heart” of the reactor, strong enough – according to ITER – to lift an aircraft carrier.
For the uninitiated: Tokamaks are doughnut-shaped vessels that contain superheated plasma for nuclear fusion, the energy reaction that powers stars like our Sun. Tokamaks contain the plasma by generating very strong magnetic fields, which is why ITER’s central electromagnet is important.
ITER is designed to confirm that nuclear fusion is a viable source of energy, although none of the reactor’s power will be used to power anything. ITER is simply a giant and expensive technology demonstrator that is getting closer and closer to flipping the switch and recreating the sun’s energy here on Earth. It is a massive collaboration involving more than 30 countries that aims to prove that the energy from fusion – essentially the collision of atoms to form other atoms, releasing enormous amounts of energy – can be harnessed and turned into a commercially viable and essentially limitless source of electricity.
The newly completed magnetic system will not work on its own. A central electromagnet joins six massive ring-shaped poloidal magnets built and shipped from Europe, China and Russia to form a 3,000-ton (2,721-ton) superconductor system cooled to -452.2 degrees Fahrenheit (-269 degrees Celsius). Together, the supercooled magnets will trap and shape a scorching plasma of 270 million degrees Fahrenheit (50 million degrees Celsius) – ten times hotter than the Sun’s core – until the atomic nuclei fuse and release ten times the energy.
Commercially viable fusion has long been the grail of clean energy, and the ITER facility is expected to be able to generate 500 megawatts of energy from just 50 megawatts of input. Such energy output would mark the beginning of self-sustaining “burning plasma” – although this goal is still a long way off.
Private companies are trying to demonstrate smaller tokamak designs as a potential way to realize future fusion, although none of these approaches has yet proven to be a breakthrough.
In 2022, the U.S. Department of Energy and Lawrence Livermore National Laboratory announced a net energy gain in the fusion reaction at the National Ignition Facility – but even this highest figure does not take into account the “wall energy” used in the experiment, making it another step in the marathon toward viable fusion power rather than a shortcut to the finish line.
ITER is not just a physical experiment, it is a geopolitical flex. Despite the tensions between the participating countries, the project has delivered the components and achieved its 2024 goals. (Last year, the collaboration also launched a private sector fusion project to share data and advance the project’s research goals.) The United States built the electromagnet and support structure, Europe is working on the vacuum chamber, Russia provided massive superconductors and busbars for the reactor, and Korea, Japan, China, and India contributed vital parts of the tokamak core.
“With ITER, we are showing that a sustainable energy future and a peaceful way forward are possible,” said Pietro Barabaschi, ITER’s director general, in a joint press release. Of course, ITER has not yet realized the “sustainable energy future” part of its project, so we should not hold our breath on the peaceful future.
Now in the assembly phase, ITER is gaining momentum on its way to its real goals, picking up the pace somewhat with the painstaking work of manufacturing its component parts. If it works, this magnetized machine could be a turning point on the road to a carbon-free energy future – even if it doesn’t contribute to the grid itself.
