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Magnet milestones move distant nuclear fusion dream closer

Teams working on two continents have marked similar milestones in their respective efforts to tap an energy source key to the fight against climate change: They’ve each produced very impressive magnets.

On Sept. 9, scientists at the International Thermonuclear Experimental Reactor in southern France took delivery of the first part of a massive magnet so strong its American manufacturer claims it can lift an aircraft carrier.

Almost 60 feet (nearly 20 meters) tall and 14 feet (more than four meters) in diameter when fully assembled, the magnet is a crucial component in the attempt by 35 nations to master nuclear fusion.

Massachusetts Institute of Technology scientists and a private company announced separately this week that they, too, have hit a milestone with the successful test of the world’s strongest high temperature superconducting magnet that may allow the team to leapfrog ITER in the race to build a ‘sun on earth.’

Unlike existing fission reactors that produce radioactive waste and sometimes catastrophic meltdowns, proponents of fusion say it offers a clean and virtually limitless supply of energy. If, that is, scientists and engineers can figure out how to harness it &midash; they have been working on the problem for nearly a century.

Rather than splitting atoms, fusion mimics a process that occurs naturally in stars to meld two hydrogen atoms together and produce a helium atom — as well as a whole load of energy.

Achieving fusion requires unimaginable amounts of heat and pressure. One approach to achieving that is to turn the hydrogen into an electrically charged gas, or plasma, which is then controlled in a donut-shaped vacuum chamber.

This is done with the help of powerful superconducting magnets such as the ‘central solenoid’ that General Atomics began shipping from San Diego to France this summer.

Scientists say ITER is now 75% complete; they aim to fire up the reactor by early 2026, with the ultimate goal of producing more energy than is required to heat up the plasma and provide proof that fusion technology is viable.

“The goal of ITER is to prove that fusion can be a viable and economically practical source of energy, but we are already looking ahead at what comes next,” he added. “That’s going to be key to making fusion work commercially, and we now have a good idea of what needs to happen to get there.”

Betting on nuclear energy — first fission and then fusion — is still the world’s best chance drastically cut greenhouse gas emissions to zero by 2050, said Frederick Bordry, who oversaw the design and construction of another fiendishly complex scientific machine, the Large Hadron Collider at CERN.

“When we speak about the cost of ITER, it’s peanuts in comparison with the impact of climate change,” he said. “We will have to have the money for it.”