海角大神

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

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

But with an eye on the vital role that energy plays in humanity鈥檚 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.听

鈥淐limate change is endangering our world鈥檚 future,鈥� says Deirdre Boilson, a division head at ITER, a massive fusion feasibility project in鈥痵outhern France. 鈥淭he most important thing we must do to halt climate change is move from fossil fuels to carbon-free energy alternatives.鈥�

Still, the estimated launch of the world鈥檚 first听fully operational fusion听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鈥檚 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鈥檛 depend on whether the sun is shining or the wind is blowing. In theory, one kilogram of fuel from a potential fusion plant could听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听power plant would be fundamentally safer. Fusion brings atoms together, while fission forces them apart.听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 鈥渧ery low鈥� or 鈥渓ow鈥� activity waste and 鈥渃annot pose any serious danger,鈥� the International Atomic Energy Agency听says. Skeptics, however, counter that fusion is far from perfect: It鈥檚 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听hydrogen. But once it runs out of hydrogen, it can鈥檛听keep itself going. It fizzles out.

The lab that has come closest to this break-even point 鈥� make energy versus take energy 鈥� 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).听

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鈥檚 reactor is a tenth of the volume of the still-unfinished ITER, where Dr. Boilson works. So it loses heat faster.

鈥淥ne must be open to continuous learning and growth,鈥� she says, and try to maintain a steady 鈥渞esilience in facing issues.鈥澨�

Scientists say that if today鈥檚 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.

鈥淓very day brings new challenges,鈥� says Akko Maas, a division head at ITER who like Dr. Boilson was interviewed by email. 鈥淭his requires both discipline and resilience from us all.鈥�

Collaborative, cooperative, global

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

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

Climate change is a global issue, and therefore 鈥渘eeds a global response,鈥� she adds.听

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

鈥淭he international aspect ... is one of the major challenges,鈥� Dr. Maas says. 鈥淎t the same time it provides opportunities through the cooperation. ... We are trying all together to make our contribution for a better world.鈥澨�

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.听听

Construction is currently 75% complete toward 鈥渇irst plasma,鈥� which is when experiments can begin.听That milestone is slated for 2025.

鈥淚TER is a very complex machine with more than a million components,鈥� Dr. Maas says. 鈥淭o make sure that everything will fit together requires a lot of discipline.鈥�

He adds: 鈥淎s 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.鈥� 听

A fusion experiment is powered by the same nuclear reaction that鈥� fuels the sun. ITER runs on two isotopes of hydrogen: deuterium and tritium. A doughnut-shaped structure, known as a tokamak machine, turns鈥痝aseous 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鈥檚 essentially an artificial star: It runs on continuous fusion reactions fueled by plasma, a super high-energy, charged gas.听

鈥淭he magnets basically keep this superhot plasma away from the walls of the vessel and therefore don鈥檛 damage it,鈥� Dr. Boilson says. 鈥淚t鈥檚 like creating a suspended sun inside a cage.鈥澨�

Heat is an essential ingredient. It鈥檚 part of the recipe. So scientists find themselves acting like Goldilocks: The temperature of the plasma must be 鈥渏ust right鈥� 鈥� not too hot, not too cold. That 鈥渏ust right鈥� plasma temperature at ITER will reach 150 million degrees Celsius 鈥� a very, very hot 鈥減orridge.鈥�

Discipline, faith, hope

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

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.听

鈥淎s a scientist, it is easy to have 鈥榝aith鈥� when the science is understood,鈥� Dr. Boilson says. 鈥淭he understanding of the physics of fusion is already there,鈥� she adds. 鈥淭he 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.鈥�