We go behind the scenes of the world’s largest nuclear fusion device in an effort to harness energy from the same reaction that powers the Sun and stars.
In the heart of Provence, some of the brightest scientific minds on the planet are setting the stage for what is billed as the world’s largest and most ambitious scientific experiment.
“We are building probably the most complex machine ever designed,” confides Laban Coblentz.
The task at hand is to demonstrate the feasibility of exploiting nuclear fusion – the same reaction that powers our Sun and stars – on an industrial scale.
To do this, the world’s largest magnetic confinement chamber, or tokamak, is being built in southern France to generate net energy.
The International Thermonuclear Experimental Reactor (ITER) Project Agreement was formally signed in 2006 by the United States, EU, Russia, China, India and South Korea at the Elysée Palace in Paris.
There are now more than 30 countries collaborating in the effort to build the experimental device, which is expected to weigh 23,000 tons and withstand temperatures of up to 150 million degrees Celsius when completed.
“In a way, this is like a national laboratory, a large research institute. But in reality it is the convergence of national laboratories from 35 countries,” Coblentz, head of communications at ITER, told Euronews Next.
How does nuclear fusion work?
Nuclear fusion is the process by which two light atomic nuclei fuse to form a single heavier one, generating a massive release of energy.
In the case of the Sun, the hydrogen atoms in its core are fused together by simple gravitational pressure.
Meanwhile, here on Earth, two main methods for generating fusion are being explored.
“The first one, you may have heard it at the National Ignition Facility in the United States,” Coblentz explained.
“You take a very, very small piece – about the size of a peppercorn – of two forms of hydrogen: deuterium and tritium. And you shoot lasers at them. So, you’re doing the same thing. You’re also crushing the pressurization. Since you’re adding heat you get an explosion of energy, E = mc². A small amount of matter is converted into energy.”
The ITER project focuses on the second possible path: magnetic confinement fusion.
“In this case, we have a very large chamber, 800 m³, and we put a very small amount of fuel – 2 to 3 g of fuel, deuterium and tritium – and we get it up to 150 million degrees through various heating systems,” said Laban.
“That’s the temperature at which the velocity of these particles is so high that instead of repelling each other with their positive charge, they combine and fuse. And when they fuse, they emit an alpha particle and emit a neutron.”
In the tokamak, charged particles are confined by a magnetic field, except for the highly energetic neutrons that escape and hit the chamber wall, transfer their heat, and then heat the water flowing behind the wall.
In theory, the energy would be harnessed from the resulting steam driving a turbine.
“This is, if you like, the successor to a long line of research devices,” explained Richard Pitts, section chief of ITER’s science division.
“The field has been studying tokamak physics for about 70 years, since the first experiments were designed and built in Russia in the 1940s and 1950s,” he added.
According to Pitts, the first tokamaks were small tabletop devices.
“Then, little by little, they get bigger and bigger, and bigger, because we know – from our work on these smaller devices, from our small to large scale studies – that to get net fusion energy out of these things, we have to we have to make a big one like this,” he said.
Advantages of fusion
Nuclear power plants have been around since the 1950s and use a fission reaction, where the atom is split in a reactor, releasing a huge amount of energy in the process.
Fission has the clear advantage of already being a proven and established method, with over 400 nuclear fission reactors in operation today around the world.
But while nuclear disasters have been a rare event in history, the catastrophic meltdown of Chernobyl’s reactor 4 in April 1986 is a stark reminder that they are never entirely risk-free.
Additionally, fission reactors also have to contend with safely managing large amounts of radioactive waste, which typically gets buried deep in geological repositories.
In contrast, ITER notes that a fusion plant of similar scale would generate energy from a much smaller amount of chemical input, just a few grams of hydrogen.
“The safety effects are not even comparable,” Coblentz noted.
“You only have 2 or 3 g of material. Also, the material in a fusion plant, deuterium and tritium, and the material that comes out, non-radioactive helium and a neutron, are all harnessed. So there’s no residue, for so to speak, and the inventory of radioactive material is extremely, extremely small,” he added.
Failures in the ITER project
The challenge with fusion, Coblentz points out, is that these nuclear reactors remain extremely difficult to build.
“You try to get something up to 150 million degrees. You try to make it the scale you need and so on. It’s just a difficult thing to do,” he said.
Certainly, the ITER project struggled with the complexity of this gigantic undertaking.
The original ITER project timeline set 2025 as the date for the first plasma, with full commissioning of the system set for 2035.
But component setbacks and delays related to COVID-19 have led to a shift in the timeline for commissioning the system and an increasing budget to cope.
The initial estimated cost for the project was 5 billion euros, but has grown to more than 20 billion euros.
“We’ve already run into challenges simply due to the complexity and the multitude of unique materials, unique components in a unique machine,” Coblentz explained.
A significant obstacle was the misalignment of the welding surfaces of the segments of the vacuum chamber produced in South Korea.
“The ones that came came with such a nonconformity in the edges where you weld them together that we have to redo those edges,” Coblentz said.
“It’s not rocket science in that particular case. It’s not even nuclear physics. It’s just working and getting things done with an incredible degree of precision, which has been difficult,” he added.
Coblentz says the project is currently in a resequencing process, hoping to get as close as possible to the 2035 goal for starting fusion operations.
“Rather than focus on what our dates were before the first plasma, the first test of the machine in 2025, and then a series of four phases to initially get to fusion energy in 2035, we will simply skip the first plasma. have the testing done another way so we can meet that date as much as possible,” she said.
As far as international collaborations go, ITER is something of a unicorn in how it has weathered the headwinds of geopolitical tensions between many of the nations involved in the project.
“These countries are obviously not always aligned ideologically. If you look at the flags on the Alphabet construction site, China flies next to Europe, Russia flies next to the United States,” Coblentz noted.
“There was no certainty that those countries would commit to working together for 40 years. There will never be any certainty that there would not be conflicts.”
Coblentz attributes the project’s relative strength to the fact that making nuclear fusion operational is a common, generational dream.
“This is what unites this force. And this is why it has survived the current sanctions that Europe and others have against Russia in the current situation with Ukraine,” he added.
Climate change and clean energy
Given the scale of the challenge posed by climate change, it’s no wonder that scientists are racing to find a carbon-free energy source to power our world.
But an abundant supply of fusion energy is still a long way off, and even ITER admits that their project represents the long-term answer to energy concerns.
In response to the idea that fusion will come too late to help fight the climate crisis in any meaningful way, Coblentz says fusion energy may have a role to play in the future as well.
“What if we actually had sea level rise to the point where we started needing energy consumption to move cities? If we start seeing energy challenges on that scale, it really becomes obvious the answer to your question,” he said.
“The longer we wait for the fusion to arrive, the more we will need it. So the smart move is: get it here as fast as possible.”
For more on this story, watch the video in the media player above.