One of the world’s most powerful magnets is the Central Solenoid of the megaproject ITER. It will be as tall as a six-story building, can lift an aircraft carrier, and is designed to play a central role in an upcoming experiment that might just provide humanity with the means to produce limitless energy without harming the planet.
The first module of the Central Solenoid is now embarking on a long journey from California to France this week, according to a joint announcement on Tuesday from ITER and General Atomics, a company that invested a decade into its design and fabrication. There, it will be integrated into ITER—an unprecedented machine named after the Latin word for “the way”—that aims to pioneer nuclear fusion, a long-sought form of carbon-free energy akin to a “Sun on Earth.”
The module will be loaded into a special 24-axle transport vehicle that will drive only at night due to its sheer size until it reaches the coast of Texas, where it will be placed on a ship due to arrive in Marseilles, France, in late August.
Weighing an extraordinary 250,000 pounds, the magnet is the first of seven modules (including one spare) that will make this transatlantic trip from General Atomics’ Magnet Technologies Center in Poway, California, to the emerging ITER complex in Cadarache, France over the next few years. Once there, they will be carefully stacked at the center of the fusion experiment’s torus design, which is known as a tokamak.
“It's an incredible feeling,” said John Smith, director of engineering and projects at General Atomics, in a call. “It's been a 10-year-plus journey to get to this point, and it's the culmination of a lot of effort between an incredible team here at General Atomics and our partners at US ITER and the ITER organization in France to be able to complete this module—the manufacturing of it—to test it, and now know that it's going to work when it goes to ITER.”
The dream of power generation through nuclear fusion dates back decades, and has become a much-anticipated means to mitigate climate change and meet the world’s energy demands. The basic idea is to harness the energy produced by the fusion of atomic nuclei, the same reaction that powers the Sun and other stars, providing a huge amount of power without the meltdown risks that come with traditional nuclear fission plants or the dangerous climate-altering emissions produced by fossil fuels.
But the technical challenges of developing fusion reactors are so colossal that this mode of power generation has long seemed as if it is perpetually on the horizon. ITER is a collaboration between 35 partner nations designed to overcome some of these obstacles, providing a practical platform for future pilot plants that can be hooked into electricity grids decades from now.
“ITER is a strange experiment, unlike anything in history, because of the combination of the technological challenges,” said Laban Coblentz, head of communication at ITER in France, in a call. “It is a collaborative research experiment with countries that, in the news, are not always seen as getting along—China, Russia, the US, and all of Europe.”
“It is a unique vision that changing the energy legacy for our children is so important that we can actually be united in this sort of common cause,” he added.
When the full Central Solenoid is complete, it will be able to generate a magnetic force of 13 Tesla, which is about 280,000 times stronger than Earth’s magnetic field, making it the most powerful solenoid ever built. The finished structure will contain 26.7 miles—a full marathon’s worth—of coiled superconductor material that was manufactured in Japan.
“If you talk to an engineer about the Central Solenoid, and give dimensions, you’ll say things like: ‘It's strong enough to lift an aircraft carrier, or it's a magnet that is nearly 60-feet-high, yet it has to be positioned along the central axis of the machine with a precision in the range of millimeters,’” Coblentz said. “An engineer will say that's insane, rightly.”
Despite those immense challenges, the ITER team is on track to perform one of its major goals, known as “first plasma,” in 2025. This test will assess the machine’s ability to generate a hydrogen plasma, ten times hotter than the Sun, which will provide an essential foundation for subsequent fusion experiments.
“In a fusion device, the plasma is what the fusion reaction occurs in,” Smith explained. “That initial first plasma shows you can create plasma and contain it in the magnetic field” demonstrating that “the ITER device is working.”
The next big step after the demonstration of first plasma will be the initiation of energy production from nuclear fusion at ITER, currently scheduled around 2035. At this point, the machine will fuse the hydrogen isotopes deuterium and tritium to generate energy, a reaction that has already been successfully demonstrated in other tokamaks.
However, no project has ever been able to reach a “plasma energy break-even point” at which the energy output exceeds the input. The Joint European Torus (JET) in the UK holds the current record for input-output ratio, having managed to produce 67 percent of the energy output that was required to fuel the fusion process.
ITER aims to blow past the break-even point to produce 10 times the thermal energy output from fusion that is required to heat the plasma. The project also plans to demonstrate that these energy levels can be maintained for hundreds of seconds at a time, providing an important bridge to potential commercial fusion plants of the future, assuming they ever materialize.
“How rapidly can we make fusion a reality? Part of it is clearly due to engineering challenges and physics challenges that are real, no question,” Coblentz said. “But part of it is also, without question, due to investment: How badly do we want this?”
“There are many, many different questions that go into that calculus and nations will make their own choices,” he continued. “Investors, whether they are governments or private investors, will help to determine what we can research in parallel, and how soon we can bring fusion energy to the grid.”
Though the ultimate realization of such an ambitious achievement is not certain, the impending voyage of the first module of the Central Solenoid represents a tangible step toward the longstanding dream of powering our planet with a constellation of artificial stars in the form of fusion plants.
“To be in the forefront of a technology effort like this is astonishing,” Smith concluded. “On the grandest scale, being part of something that could solve the world's energy problems is a privilege.”