Quest for nuclear fusion is advancing – powered by scientific grit

Science is slow: It’s doing the same difficult thing over and over, observing, changing, doing it again. It’s setting up a thousand little things while waiting for the big thing to finally happen. 

The quest for nuclear fusion – a carbon-free, potentially limitless power source – is exactly that. Aspirations have endured for decades. The path has been long, winding, and full of frustration. 

But with an eye on the vital role that energy plays in humanity’s future, researchers are continuing to come together to try to make it happen. In the fight against climate change, they have been making headway, including with an important milestone reached just last month. 

“Climate change is endangering our world’s future,” says Deirdre Boilson, a division head at ITER, a massive fusion feasibility project in southern France. “The most important thing we must do to halt climate change is move from fossil fuels to carbon-free energy alternatives.”

Still, the estimated launch of the world’s first fully operational fusion power plant is at least three decades away. Yet after decades of dismissal as a fringe pipe dream, fusion power is starting to look like it just might happen.

A win for Earth’s climate?

Like renewables such as wind, solar, and geothermal power, fusion has the potential to be abundant and virtually inexhaustible. And backers say it wouldn’t depend on whether the sun is shining or the wind is blowing. In theory, one kilogram of fuel from a potential fusion plant could provide as much power as 10 million kilograms of fossil fuel.

One more thing: Where traditional nuclear power (in fission reactors) has resulted in tragic plant meltdowns, a fusion power plant would be fundamentally safer. Fusion brings atoms together, while fission forces them apart. Unlike fission, fusion is a self-limiting process, not a chain reaction: Without fuel, it quickly comes to a stop. And though a fusion power plant would generate radioactive waste, it would be classified as either “very low” or “low” activity waste and “cannot pose any serious danger,” the International Atomic Energy Agency says. Skeptics, however, counter that fusion is far from perfect: It’s expensive, to start.

For now, fusion power remains a dream. No fusion experiment has been able to fuel itself. Instead, researchers must use energy to make energy. They inject heat to help the system react and fuse, like how steam heats milk in a cappuccino machine. As the plasma gets hotter, it releases energy using hydrogen. But once it runs out of hydrogen, it can’t keep itself going. It fizzles out.

The lab that has come closest to this break-even point – make energy versus take energy – is JET, the Joint European Torus in the United Kingdom, which generated 16 megawatts of fusion power, versus 24 megawatts of power that was used to heat the plasma (a so-called Q ratio of 0.67). 

In February, JET announced that its reactor experiment achieved a new milestone: It generated more than twice as much heat as its last record (59 megajoules in 2022, versus 21.7 megajoules in 1997). JET’s reactor is a tenth of the volume of the still-unfinished ITER, where Dr. Boilson works. So it loses heat faster.

“One must be open to continuous learning and growth,” she says, and try to maintain a steady “resilience in facing issues.” 

Scientists say that if today’s experiments are modest in scale, creating energy for just a few seconds at a time, they are steppingstones toward the goal of sustained energy production.

“Every day brings new challenges,” says Akko Maas, a division head at ITER who like Dr. Boilson was interviewed by email. “This requires both discipline and resilience from us all.”

Collaborative, cooperative, global

Like fusion, the construction underway at ITER is an effort that brings things together, rather than pushing them apart. It’s a highly structured international blend of labor and resources. 

“Working at ITER, knowing that your day job helps to address one of the biggest challenges our world is facing – climate change – is in itself an inspiration, and a good reason to get up in the morning motivated to give your best to this project,” Dr. Boilson says. 

Climate change is a global issue, and therefore “needs a global response,” she adds. 

The United States is working alongside six other members: China, India, Japan, Korea, Russia, and the European Union. (The war in Ukraine’s impact on ITER is at this point unclear, but the project was built in the spirit of international collaboration, so the scientific community is hoping for peace.) 

“The international aspect ... is one of the major challenges,” Dr. Maas says. “At the same time it provides opportunities through the cooperation. ... We are trying all together to make our contribution for a better world.” 

Wrangling plasma, creating energy

The project is essentially cobbled together, as the members must work collaboratively. Components are constructed across the globe and shipped to France. The machine itself is built and assembled on-site, and integrating these components can take time and perseverance.  

Construction is currently 75% complete toward “first plasma,” which is when experiments can begin. That milestone is slated for 2025.

“ITER is a very complex machine with more than a million components,” Dr. Maas says. “To make sure that everything will fit together requires a lot of discipline.”

He adds: “As I always say to my children, I am proud to work on something that might (and I believe it will) provide a solution to the energy problems that we have today.”  

A fusion experiment is powered by the same nuclear reaction that  fuels the sun. ITER runs on two isotopes of hydrogen: deuterium and tritium. A doughnut-shaped structure, known as a tokamak machine, turns gaseous hydrogen into a superhot, charged plasma that brings hydrogen atoms together to form a heavier element (helium), releasing energy (neutrons) using strategically placed magnetic coils. It’s essentially an artificial star: It runs on continuous fusion reactions fueled by plasma, a super high-energy, charged gas. 

“The magnets basically keep this superhot plasma away from the walls of the vessel and therefore don’t damage it,” Dr. Boilson says. “It’s like creating a suspended sun inside a cage.” 

Heat is an essential ingredient. It’s part of the recipe. So scientists find themselves acting like Goldilocks: The temperature of the plasma must be “just right” – not too hot, not too cold. That “just right” plasma temperature at ITER will reach 150 million degrees Celsius – a very, very hot “porridge.”

Discipline, faith, hope

Sometimes, the discipline of doing science can feel like hope: It’s all about working toward something, waiting for it to be revealed. There’s hope in that. There may even be faith in that. 

This is not rolling a rock up a hill for eternity. The goal at ITER is to demonstrate that the machine can make more energy than the energy it takes to keep it running. Although setbacks have accompanied the progress, and years of persistence lie ahead, these researchers see the goal as achievable. 

“As a scientist, it is easy to have ‘faith’ when the science is understood,” Dr. Boilson says. “The understanding of the physics of fusion is already there,” she adds. “The combination of different devices and collaborative scientific endeavors brings experience, which allows us to have confidence in the machine we are building, and the physics behind it.”