In the heart of Provence, some of the world's brightest scientific minds are setting the stage for what is being called the world's largest and most ambitious scientific experiment.
"We are building perhaps the most complex machine ever designed," confides Laban Coblentz.
The task ahead is to demonstrate the feasibility of harnessing 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 the south of France to generate net energy.
The International Thermonuclear Experimental Reactor (ITER) project agreement was formally signed by the US, EU, Russia, China, India and South Korea at the Elysée Palace in Paris in 2006.
More than 30 countries are now involved in building the experimental device, which is expected to weigh 23,000 tonnes and withstand temperatures of up to 150 million °C when completed.
"In a way this looks like a national laboratory, a big research institute. But it is the convergence of the national laboratories, actually of 35 countries," Coblentz, ITER's head of communications, told Euronews Next.
How does nuclear fusion work?
Nuclear fusion is the process in which two light atomic nuclei fuse to form one heavier nucleus, releasing an enormous amount of energy.
In the case of the Sun, hydrogen atoms in the core are fused together by the enormous amount of gravitational pressure.
We have encountered challenges before, simply because of the complexity and the multitude of unique materials, unique components in a unique machine.
Meanwhile, here on Earth, two major methods for generating fusion are being explored.
"You may have heard the first one at the National Ignition Facility in the US," Coblentz explained.
"You take a tiny bit - the size of a peppercorn - of two forms of hydrogen: deuterium and tritium. And you shoot lasers at it. So you do the same thing. You also crush the pressure. When you add heat you get a explosion of energy, E = mc². A small amount of matter is converted into energy".
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The ITER project focuses on the second possible route: nuclear fusion through magnetic confinement.
"In this case we have a very large chamber, 800 m³, and we put a very small amount of fuel in it - 2 to 3 g of fuel, deuterium and tritium - and we get it up to 150 million degrees through different heating systems," said Laban .
"That's the temperature at which the speed 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 give off an alpha particle and a neutron."
In the tokamak, the charged particles are confined by a magnetic field, except that the high-energy neutrons that escape and hit the wall of the chamber transfer their heat and thereby heat the water flowing behind the wall.
Theoretically, energy would be harnessed by the resulting steam driving a turbine.
"This is, if you like, the successor to a long line of research equipment," explains Richard Pitts, section leader of ITER's science department.
"The field has been researching 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, early 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, our scaling studies from small to bigger to bigger - that in order to get net fusion energy out of these things, we have to make one as big as this," he said.
Benefits of merger
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.
Nuclear fission has the distinct advantage of already being the proven method, with more than 400 fission reactors currently in operation worldwide.
But while nuclear disasters are rare in history, the catastrophic meltdown of reactor 4 at Chernobyl in April 1986 is a stark reminder that they are never entirely without risks.
In addition, fission reactors also have to deal with the safe management of large amounts of radioactive waste, which is usually buried deep underground in geological repositories.
In contrast, ITER notes that a fusion plant of similar size could generate power from a much smaller amount of chemical inputs, just a few grams of hydrogen.
"The safety effects are not even comparable," Coblentz noted.
'You only have 2 to 3 grams of material. In addition, the material in a fusion plant, deuterium and tritium, and the material that comes out of it, non-radioactive helium and a neutron, are all utilized. So there is no remainder left. , so to speak, and the inventory of radioactive material is extremely, extremely small," he added.
Setbacks for the ITER project
The challenge with fusion, Coblentz points out, is that these nuclear reactors remain extremely difficult to build.
"You're trying to take something to 150 million degrees. You're trying to get it to the scale that it needs to be and so on. It's just hard to do," he said.
Certainly, the ITER project has struggled with the complexity of this massive undertaking.
The original timeline for the ITER project set 2025 as the date for first plasma, with full commissioning of the system planned for 2035.
But component setbacks and COVID-19-related delays have led to a shifting timeline for system commissioning and an associated ballooning budget.
The initial cost estimate for the project was €5 billion, but has grown to over €20 billion.
"We've encountered challenges before simply because of the complexity and the multitude of premium materials, premium components in a unique machine," Coblentz explains.
A major setback involved misalignment in the weld surfaces of vacuum chamber segments manufactured in South Korea.
"The ones that have arrived have arrived with enough non-conformance in the edges where you weld them together that we have to redo those edges," Coblentz said.
"In that particular case, it's not rocket science. It's not even nuclear physics. It's just machining and getting things to an incredible degree of precision, which was difficult," he added.
Coblentz says the project is currently in a realignment process, hoping to stay as close as possible to the 2035 target for the start of merger operations.
"Rather than focus on what our data was before a first plasma, the first test of the machine in 2025, and then a series of four stages to get to fusion energy in 2035, we'll just skip the first plasma . Make sure that testing is done in a different way so that we can stick to that date as much as possible," he said.
International cooperation
In terms of international cooperation, ITER is something of a unicorn in the way it has weathered the headwinds of geopolitical tensions between many of the countries involved in the project.
The longer we wait for nuclear fusion to arrive, the more we need it. So the smart money is: get it here ASAP.
"These countries are of course not always ideologically aligned. If you look at the signature flags in Alphabet's workplace, China is flying next to Europe, and Russia is flying next to the United States," Coblentz noted.
"It was not certain that these countries would commit to working together for a period of forty years. There will never be certainty that conflicts would not arise."
Coblentz attributes the project's relative health to the fact that kick-starting nuclear fusion has been a common dream for generations.
"That's what brings this force together. And that is why it has survived the current sanctions that Europe and others have imposed on 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 scientists are rushing to find a carbon-free energy source that can power our world.
But an abundant supply of fusion energy is still far away, and even ITER admits that their project is the long-term answer to energy problems.
Responding to the idea that fusion will come too late to help combat the climate crisis in a meaningful way, Coblentz argues that fusion energy could play a role in the future.
"If we really have sea level rise to the extent that we're going to need the energy consumption to move cities? If we start to see energy challenges on that scale, the answer to your question becomes very clear," he said.
"The longer we wait for nuclear fusion to arrive, the more we need it. So the smart money is: get it here as soon as possible."
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