2023-12-19 20:33:28
We go behind the scenes of the world’s largest nuclear fusion device, which attempts to harness the energy from the reaction that powers the Sun and stars.
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In the heart of Provence, some of the brightest scientific minds on the planet are paving the way for what is considered the largest and most ambitious scientific experiment in the world.
“We are building arguably the most complex machine ever designed“, confides Laban Coblentz.
It is 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 containment chamber, or tokamak, is being built in the south of France to produce net energy.
The agreement for the International Thermonuclear Experimental Reactor (ITER) project was officially signed in 2006 by the United States, the European Union, Russia, China, India and South Korea at the Palace of the Élysée in Paris.
More than 30 countries are currently collaborating on the construction of the experimental device, Whoexpected to weigh 23,000 tonnes and withstand temperatures of up to 150 million degrees Celsius when it is completed.
“In a way, it is a national laboratory, a major research institute. But it is the convergence of national laboratories from 35 countries“, says Laban Coblentz, ITER communications manager, to Euronews Next.
How does nuclear fusion work?
Nuclear fusion is the process by which two light atomic nuclei fuse to form a single, heavier nucleusgenerating a massive release of energy.
In the case of the Sun, the hydrogen atoms in its core are fused together under the effect of gravitational pressure.
Meanwhile, on Earth, two main methods are being explored to generate fusion.
“The first, which you may have heard about at the National Ignition Facility in the United States“explained Laban Coblentz.
“You take a very, very small sample – the size of a peppercorn – of two forms of hydrogen: deuterium and tritium. And you bombard him with lasers. So you do the same thing [que le soleil]. You crush the pressure while adding heat and you get a burst of energy, E = mc². A small amount of matter is converted into energy“.
The ITER project focuses on the second possible path: fusion by magnetic confinement.
“In this case, we have a very large chamber, 800 m³, in which we place a very small quantity of fuel – 2 to 3 g of fuel, deuterium and tritium – which we bring to 150 million degrees thanks to to various heating systems“explained Laban Laban.
“This is 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 merge, they emit an alpha particle and a neutron“.
In the tokamak, the charged particles are confined by a magnetic field, except for the very energetic neutrons which escape and strike the chamber wall, transfer their heat and thus heat the water flowing behind the wall.
Theoretically, energy would be produced by the resulting steam which would drive a turbine.
“It is, in a way, the successor of a long series of research devices“, explains Richard Pitts, section head of ITER’s scientific division.
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“The physics of tokamaks has been studied for about 70 years, since the first experiments were designed and built in Russia in the 1940s and 1950s.“, add-tilt.
According to Richard Pitts, the first tokamaks were small tabletop devices.
“Then, little by little, they became larger and larger, because we know – thanks to our work on these small devices and our studies of progressive scaling to larger models – that to obtain a power of clean fusion from these devices, a tokamak of this size is necessary“, he declares.
Advantages of the merger
Nuclear power plants have been around since the 1950s and exploit the fission reaction, whereby the atom is split in a reactor, releasing a massive amount of energy.
Fission has the clear advantage of being a method already tried and tested, with more than 400 nuclear fission reactors in operation around the world today.
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But if nuclear disasters have been rare in history, the catastrophic meltdown of reactor 4 at Chernobyl in April 1986 reminds us that they are never completely devoid of risks.
Furthermore, fission reactors produce large quantities of radioactive wastewhich are generally buried in deep geological deposits.
In contrast, ITER notes that a fusion plant of similar size would produce energy from a much smaller amount of chemical inputs, namely a few grams of hydrogen.
“The safety effects are not even comparable“, notes Laban Coblentz.
“You only have 2 to 3 g of material. In addition, the materials present in a fusion plant, deuterium and tritium, and the materials released from them, non-radioactive helium and a neutron, are all exploited. So there are no residuesso to speak, and the inventory of radioactive materials is extremely minimal“, he adds.
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The setbacks of the ITER project
The challenge of merger, underlines Laban Coblentz, is that these nuclear reactors remain extremely difficult to build.
“You’re trying to take matter to 150 million degrees. You try to do it at the scale needed and so on. It’s difficult to achieve“, he declares.
It is certain that the ITER project encountered the complexity of this gargantuan undertaking.
The initial schedule of the ITER project envisaged obtaining the first plasma in 2025 and full commissioning of the system in 2035.
However, component setbacks and delays related to the COVID-19 outbreak caused a shift in the system’s go-live schedule and a resulting budget blowout.
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The initial estimate of the cost of the project was 5 billion euros, but it rose to more than 20 billion euros.
“We encountered challenges due to the complexity and multitude of new materials and components needed to create a one-of-a-kind machine“explained Laban Coblentz.
One of the biggest setbacks was the misalignment of the solder surfaces of the vacuum chamber segments manufactured in South Korea.
“Those that arrived had enough non-conformities on the soldering points that we had to redo them.“, says Laban Coblentz.
“It’s not rocket science in this specific case. It’s not even nuclear physics. But it’s still a matter of machining and achieving an incredible degree of precision, which has been difficult“, he adds.
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Laban Coblentz explains that the project is currently engaged in a resequencing processhoping to get as close as possible to the 2035 target for the start of fusion operations.
“Rather than focusing on the expected dates of obtaining the first plasma, a first test of the machine in 2025, and then a series of four steps to reach fusion energy in 2035, we will simply skip the first plasma. We will ensure that testing is carried out in another manner to meet this date as closely as possible“, he declares.
Collaboration internationale
Regarding international collaborations, ITER is a kind of unicorn that was able to resist the geopolitical tensions between many countries involved in the project.
“These countries are obviously not always ideologically aligned. If you look at the flags on the job site in alphabetical order, China flies next to Europe, Russia next to the United States“, notes Laban Coblentz.
“For these countries to commit to working together for 40 years, there was no certainty. There will never be certainty that there will be no conflicts“.
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According to Laban Coblentz, the relative health of the project can be explained by the fact that the implementation of nuclear fusion is a common and generational dream.
“This is what brings together the forces present. 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 adds.
Climate change and clean energy
Given the scale of the challenge posed by climate change, it’s no wonder that scientists are working to find a carbon-free energy source to power our world.
But the supply of fusion energy at the industrial level is still far away, and even ITER admits that his project represents the long-term response to energy concerns.
In response to the idea that fusion will come too late to make a significant contribution to tackling the climate crisis, Laban Coblentz argues that fusion energy may have a role to play in the more distant future.
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“What if sea level rise is such that we need enormous energy consumption to move cities? If we start facing energy challenges on this scale, the answer to your question becomes really obvious.“, he declares.
“The longer we wait for the merger to happen, the more we need it. The smartest solution is therefore to put it in place as quickly as possible.“.
For more on this story, watch the video in the media player above.
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