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Here’s how scientists reached nuclear fusion ‘ignition’ for the first time.

The experiment, performed in 2022, also revealed a never-before-seen phenomenon

In December 2022, scientists at the National Ignition Facility (pictured) achieved nuclear fusion “ignition,” in which the energy produced by the fusing of atomic nuclei exceeds that needed to kick the fusion off.

Jason Laurea/LLNL

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By Emily Conover

February 16, 2024 at 9:30 am

One of nuclear fusion’s biggest advances wouldn’t have happened without some impeccable scientific artistry.

In December 2022, researchers at Lawrence Livermore National Laboratory in California created fusion reactions that produced an excess of energy — a first. In the experiment, 192 lasers blasted a small chamber, setting off fusion reactions — in which smaller atomic nuclei merge to form larger ones — that released more energy than initially kicked them off ( SN: 12/12/22 ). It’s a milestone known as “ignition,” and it has been decades in the making.

Now, researchers have released details of that experiment in five peer-reviewed papers published online February 5 in Physical Review Letters and Physical Review E . The feat demanded an extraordinary level of finesse, tweaking conditions just so to get more energy out of the lasers and create the ideal conditions for fusion.

The work is “exquisitely beautiful,” says physicist Peter Norreys of the University of Oxford. Norreys, who was not involved with the research, compares the achievement to conducting a world-class orchestra: Different elements of the experiment had to be meticulously coordinated and precisely timed.

Scientists also discovered a long-predicted heating effect that could expose the physics of other violent environments, such as exploding stars called supernovas. “People say [physics is] a dry subject,” Norreys says. “But I always think that physics is at the very forefront of creativity,”

The road to nuclear fusion’s big break

Fusion, the same process that takes place in the sun, is an appealing energy source. Fusion power plants wouldn’t emit greenhouse gases. And unlike current nuclear fission power plants, which split atomic nuclei to produce energy, nuclear fusion plants wouldn’t produce dangerous, long-lived radioactive waste. Ignition is the first step toward harnessing such power.

Generating fusion requires extreme pressures and temperatures. In the experiment, the lasers at LLNL’s National Ignition Facility pelted the inside of a hollow cylinder, called a hohlraum, which is about the size of a pencil eraser. The blast heated the hohlraum to a sizzling 3 million degrees Celsius — so hot that it emitted X-rays. Inside this X-ray oven, a diamond capsule contained the fuel: two heavy varieties of hydrogen called deuterium and tritium. The radiation vaporized the capsule’s diamond shell, triggering the fuel to implode at speeds of around 400 kilometers per second, forming the hot, dense conditions that spark fusion.

Previous experiments had gotten tantalizingly close to ignition ( SN: 8/18/21 ). To push further, the researchers increased the energy of the laser pulse from 1.92 million joules to 2.05 million joules. This they accomplished by slightly lengthening the laser pulse, which blasts the target for just a few nanoseconds, extending it by a mere fraction of a nanosecond. (Increasing the laser power directly, rather than lengthening the pulse, risked damage to the facility.)

The team also thickened the capsule’s diamond shell by about 7 percent — a difference of just a few micrometers — which slowed down the capsule’s implosion, allowing the scientists to fully capitalize on the longer laser pulse.  “That was a quite remarkable achievement,” Norreys says.

But these tweaks altered the symmetry of the implosion, which meant other adjustments were needed. It’s like trying to squeeze a basketball down to the size of a pea, says physicist Annie Kritcher of LLNL, “and we’re trying to do that spherically symmetric to within 1 percent.”

That’s particularly challenging because of the mishmash of electrically charged particles, or plasma, that fills the hohlraum during the laser blast. This plasma can absorb the laser beams before they reach the walls of the hohlraum, messing with the implosion’s symmetry.

To even things out, Kritcher and colleagues slightly altered the wavelengths of the laser beams in a way that allowed them to transfer energy from one beam to another. The fix required tweaking the beams’ wavelengths by mere angstroms — tenths of a billionth of a meter.

“Engineering-wise, that’s amazing they could do that,” says physicist Carolyn Kuranz of the University of Michigan in Ann Arbor, who was not involved with the work. What’s more, “these tiny, tiny tweaks make such a phenomenal difference.”

After all the adjustments, the ensuing fusion reactions yielded 3.15 million joules of energy — about 1.5 times the input energy, Kritcher and colleagues reported in Physical Review E . The total energy needed to power NIF’s lasers is much larger, around 350 million joules. While NIF’s lasers are not designed to be energy-efficient, this means that fusion is still far from a practical power source.

Another experiment in July 2023 used a higher-quality diamond capsule and obtained an even larger energy gain of 1.9, meaning it released nearly twice as much energy as went into the reactions ( SN: 10/2/23 ). In the future, NIF researchers hope to be able to increase the laser’s energy from around 2 million joules up to 3 million , which could kick off fusion reactions with a gain as large as 10.

What’s next for fusion

The researchers also discovered a long-predicted phenomenon that could be useful for future experiments: After the lasers heated the hohlraum, it was heated further by effects of the fusion reactions, physicist Mordy Rosen and colleagues report in Physical Review Letters .

Following the implosion, the ignited fuel expanded outward, plowing into the remnants of the diamond shell. That heated the material, which then radiated its heat to the hohlraum. It’s reminiscent of a supernova, in which the shock wave from an exploding star plows through debris the star expelled prior to its explosion ( SN: 2/8/17 ).

“This is exactly the collision that’s happening in this hohlraum,” says Rosen, of LLNL, a coauthor of the study. In addition to explaining supernovas, the effect could help scientists study the physics of nuclear weapons and other extreme situations.

NIF is not the only fusion game in town. Other researchers aim to kick off fusion by confining plasma into a torus, or donut shape, using a device called a tokamak. In a new record, the Joint European Torus in Abingdon, England, generated 69 million joules , a record for total fusion energy production, researchers reported February 8.

After decades of slow progress on fusion, scientists are beginning to get their atomic orchestras in sync.

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For First Time, Researchers Produce More Energy from Fusion Than Was Used to Drive It, Promising Further Discovery in Clean Power  and Nuclear Weapons Stewardship

WASHINGTON, D.C. — The U.S. Department of Energy (DOE) and DOE’s National Nuclear Security Administration (NNSA) today announced the achievement of fusion ignition at Lawrence Livermore National Laboratory (LLNL)—a major scientific breakthrough decades in the making that will pave the way for advancements in national defense and the future of clean power. On December 5, a team at LLNL’s National Ignition Facility (NIF) conducted the first controlled fusion experiment in history to reach this milestone, also known as scientific energy breakeven, meaning it produced more energy from fusion than the laser energy used to drive it. This historic, first-of-its kind achievement will provide unprecedented capability to support NNSA’s Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy, which would be a game-changer for efforts to achieve President Biden’s goal of a net-zero carbon economy.

“This is a landmark achievement for the researchers and staff at the National Ignition Facility who have dedicated their careers to seeing fusion ignition become a reality, and this milestone will undoubtedly spark even more discovery,” said U.S. Secretary of Energy Jennifer M. Granholm . “The Biden-Harris Administration is committed to supporting our world-class scientists—like the team at NIF—whose work will help us solve humanity’s most complex and pressing problems, like providing clean power to combat climate change and maintaining a nuclear deterrent without nuclear testing.”

“We have had a theoretical understanding of fusion for over a century, but the journey from knowing to doing can be long and arduous. Today’s milestone shows what we can do with perseverance,” said Dr. Arati Prabhakar, the President’s Chief Advisor for Science and Technology and Director of the White House Office of Science and Technology Policy .

“Monday, December 5, 2022, was a historic day in science thanks to the incredible people at Livermore Lab and the National Ignition Facility. In making this breakthrough, they have opened a new chapter in NNSA’s Stockpile Stewardship Program,” said NNSA Administrator Jill Hruby . “I would like to thank the members of Congress who have supported the National Ignition Facility because their belief in the promise of visionary science has been critical for our mission. Our team from around the DOE national laboratories and our international partners have shown us the power of collaboration.”

“The pursuit of fusion ignition in the laboratory is one of the most significant scientific challenges ever tackled by humanity, and achieving it is a triumph of science, engineering, and most of all, people,” LLNL Director Dr. Kim Budil said. “Crossing this threshold is the vision that has driven 60 years of dedicated pursuit—a continual process of learning, building, expanding knowledge and capability, and then finding ways to overcome the new challenges that emerged. These are the problems that the U.S. national laboratories were created to solve.”

“This astonishing scientific advance puts us on the precipice of a future no longer reliant on fossil fuels but instead powered by new clean fusion energy,” U.S. Senate Majority Leader Charles Schumer said. I commend Lawrence Livermore National Labs and its partners in our nation’s Inertial Confinement Fusion (ICF) program, including the University of Rochester’s Lab for Laser Energetics in New York, for achieving this breakthrough. Making this future clean energy world a reality will require our physicists, innovative workers, and brightest minds at our DOE-funded institutions, including the Rochester Laser Lab, to double down on their cutting-edge work. That’s why I’m also proud to announce today that I’ve helped to secure the highest ever authorization of over $624 million this year in the National Defense Authorization Act for the ICF program to build on this amazing breakthrough.”

“After more than a decade of scientific and technical innovation, I congratulate the team at Lawrence Livermore National Laboratory and the National Ignition Facility for their historic accomplishment,” said U.S. Senator Dianne Feinstein (CA) . “This is an exciting step in fusion and everyone at Lawrence Livermore and NIF should be proud of this milestone achievement.”

“This is an historic, innovative achievement that builds on the contributions of generations of Livermore scientists. Today, our nation stands on their collective shoulders. We still have a long way to go, but this is a critical step and I commend the U.S. Department of Energy and all who contributed toward this promising breakthrough, which could help fuel a brighter clean energy future for the United States and humanity,” said U.S. Senator Jack Reed (RI) , the Chairman of the Senate Armed Services Committee.

“This monumental scientific breakthrough is a milestone for the future of clean energy,” said U.S. Senator Alex Padilla (CA) . “While there is more work ahead to harness the potential of fusion energy, I am proud that California scientists continue to lead the way in developing clean energy technologies. I congratulate the scientists at Lawrence Livermore National Laboratory for their dedication to a clean energy future, and I am committed to ensuring they have all of the tools and funding they need to continue this important work.”

“This is a very big deal. We can celebrate another performance record by the National Ignition Facility. This latest achievement is particularly remarkable because NIF used a less spherically symmetrical target than in the August 2021 experiment,” said U.S. Representative Zoe Lofgren (CA-19) . “This significant advancement showcases the future possibilities for the commercialization of fusion energy. Congress and the Administration need to fully fund and properly implement the fusion research provisions in the recent CHIPS and Science Act and likely more. During World War II, we crafted the Manhattan Project for a timely result. The challenges facing the world today are even greater than at that time. We must double down and accelerate the research to explore new pathways for the clean, limitless energy that fusion promises.”

“I am thrilled that NIF—the United States’ most cutting-edge nuclear research facility—has achieved fusion ignition, potentially providing for a new clean and sustainable energy source in the future. This breakthrough will ensure the safety and reliability of our nuclear stockpile, open new frontiers in science, and enable progress toward new ways to power our homes and offices in future decades,” said U.S. Representative Eric Swalwell (CA-15) . “I commend the scientists and researchers for their hard work and dedication that led to this monumental scientific achievement, and I will continue to push for robust funding for NIF to support advancements in fusion research.”

LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE). Many advanced science and technology developments are still needed to achieve simple, affordable IFE to power homes and businesses, and DOE is currently restarting a broad-based, coordinated IFE program in the United States. Combined with private-sector investment, there is a lot of momentum to drive rapid progress toward fusion commercialization.

Fusion is the process by which two light nuclei combine to form a single heavier nucleus, releasing a large amount of energy. In the 1960s, a group of pioneering scientists at LLNL hypothesized that lasers could be used to induce fusion in a laboratory setting. Led by physicist John Nuckolls, who later served as LLNL director from 1988 to 1994, this revolutionary idea became inertial confinement fusion, kicking off more than 60 years of research and development in lasers, optics, diagnostics, target fabrication, computer modeling and simulation, and experimental design.

To pursue this concept, LLNL built a series of increasingly powerful laser systems, leading to the creation of NIF, the world’s largest and most energetic laser system. NIF—located at LLNL in Livermore, Calif.—is the size of a sports stadium and uses powerful laser beams to create temperatures and pressures like those in the cores of stars and giant planets, and inside exploding nuclear weapons.

Achieving ignition was made possible by dedication from LLNL employees as well as countless collaborators at DOE’s Los Alamos National Laboratory, Sandia National Laboratories, and Nevada National Security Site; General Atomics; academic institutions, including the University of Rochester’s Laboratory for Laser Energetics, the Massachusetts Institute of Technology, the University of California, Berkeley, and Princeton University; international partners, including the United Kingdom’s Atomic Weapons Establishment and the French Alternative Energies and Atomic Energy Commission; and stakeholders at DOE and NNSA and in Congress.

Scientists achieve a breakthrough in nuclear fusion. Here’s what it means.

A U.S. lab has successfully sparked a fusion reaction that released more energy than went into it. But there’s still a long way to go toward fusion as a clean energy source.

For more than 60 years, scientists have pursued one of the toughest physics challenges ever conceived: harnessing nuclear fusion, the power source of the stars , to generate abundant clean energy here on Earth. Today, researchers announced a milestone in this effort. For the first time, a fusion reactor has produced more energy than was used to trigger the reaction.

On December 5, an array of lasers at the National Ignition Facility (NIF), part of the Lawrence Livermore National Laboratory in California, fired 2.05 megajoules of energy at a tiny cylinder holding a pellet of frozen deuterium and tritium, heavier forms of hydrogen. The pellet compressed and generated temperatures and pressures intense enough to cause the hydrogen inside it to fuse. In a tiny blaze lasting less than a billionth of a second, the fusing atomic nuclei released 3.15 megajoules of energy—about 50 percent more than had been used to heat the pellet.

Though the conflagration ended in an instant, its significance will endure. Fusion researchers have long sought to achieve net energy gain, which is called scientific breakeven. “Simply put, this is one of the most impressive scientific feats of the 21st century,” U.S. Energy Secretary Jennifer Granholm said at a Washington, D.C. media briefing.

In reaching scientific breakeven, NIF has shown that it can achieve “ignition”: a state of matter that can readily sustain a fusion reaction. Being able to study the conditions of ignition in detail will be “a game-changer for the entire field of thermonuclear fusion,” says Johan Frenje, an MIT plasma physicist whose laboratory contributed to NIF’s record-breaking run.

The achievement does not mean that fusion is now a viable power source. While NIF’s reaction produced more energy than the reactor used to heat up the atomic nuclei, it didn’t generate more than the reactor’s total energy use. According to Kim Budil, director of Lawrence Livermore National Laboratory, the lasers required 300 megajoules of energy to produce about 2 megajoules’ worth of beam energy. “I don’t want to give you the sense that we’re going to plug the NIF into the grid—that’s not how this works,” Budil added. “It’s a fundamental building block.”

Even so, after decades of trying, scientists have taken a major step toward fusion power. “It looks like science fiction, but they did it, and it’s fantastic what they’ve done,” says Ambrogio Fasoli, a fusion physicist at the Swiss Federal Institute of Technology in Lausanne.

Sparking fusion ignition

Though nuclear fusion and nuclear fission both draw energy from the atom, they operate differently. Today’s nuclear power plants rely on nuclear fission, which releases energy when large, heavy atoms such as uranium break apart due to radioactive decay. In fusion, however, small, light atoms such as hydrogen fuse into bigger ones. In the process, they release a small part of their combined mass as energy.

In laboratories, coaxing hydrogen nuclei to fuse into helium requires creating and confining a “plasma”—an electrically charged gas, where electrons are no longer bound to atomic nuclei—at temperatures several times hotter than inside the sun. Scientists learned decades ago how to unleash this process explosively inside hydrogen bombs, and today’s fusion reactors can make it happen in a controlled way for fleeting instants.

Since the late 1950s and early 1960s, fusion reactors have had the same basic goal: create as hot and dense a plasma as possible, and then confine that material for long enough that the nuclei within it reach ignition. The trouble is, plasma is unruly: It’s electrically charged, which means it both responds to magnetic fields and generates its own as it moves. To support fusion, it has to reach truly staggering temperatures. Yet it’s so diffuse, it easily cools off.

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Physicist Riccardo Betti, an expert on laser-driven nuclear fusion at the University of Rochester, likens the challenge of fusion ignition to burning gasoline in an engine. A small amount of gasoline mixes with air and then ignites from a spark. The spark isn’t massive, but it doesn’t have to be: All it has to do is ignite a small fraction of the gasoline-air mixture. If that tiny fraction ignites, the energy it releases is enough to ignite the rest of the fuel.

In terms of energy released, nuclear reactions pack roughly a million times more punch than chemical reactions do—and are vastly harder to get going. Past fusion experiments may have achieved the right temperatures or the right pressures or the right plasma confinement times to reach ignition, but not all those factors at once. “Basically, the spark was generated, but it wasn’t strong enough,” Betti says.

A pellet of fuel

NIF’s method of sparking the nuclear fuel starts with a peppercorn-size pellet that contains a frozen mix of deuterium and tritium, two heavier isotopes of hydrogen. This capsule is placed within a gold cylinder roughly the size of a pencil eraser that’s called a hohlraum, which is then mounted on an arm in the middle of a large, laser-studded chamber.

To trigger fusion, NIF fires 192 lasers all at once at the hohlraum, which angle into it through two holes. The beams then slam into the hohlraum’s inner surface, which causes it to spit out high-energy x-rays that rapidly heat up the outer layers of the capsule, making them burn off and fly outward. The inner part of this capsule rapidly compresses to nearly a hundred times denser than lead—which forces the deuterium and tritium inside to reach the temperatures and pressures needed for fusion.

In 1997, the National Academy of Sciences defined what “ignition” would mean for the facility , which broke ground that same year: when fusion energy released exceeds the energy of the lasers.The facility opened in 2009, and reaching this threshold ended up taking more than a decade. In August 2021, NIF reported its best-ever experimental run up to that point: 1.32 megajoules of released fusion energy for 1.92 megajoules of inputted laser energy.

The 2021 run signaled that ignition could be achieved within the NIF reactor. To finally cross the threshold, NIF researchers made a few minor tweaks, which included operating at slightly higher laser energies. “Any small changes, if you do them right, will have significant changes on the outcome,” Frenje says.

The dream of a fusion power plant

For all of NIF’s success, commercializing this style of fusion reactor wouldn’t be easy. Betti, the University of Rochester physicist, says that such a reactor would need to generate 50 to 100 times more energy than its lasers emit to cover its own energy use and put power into the grid. It’d also have to vaporize 10 capsules a second, every second, for long periods of time. Right now, fuel capsules are extremely expensive to make, and they rely on tritium, a short-lived radioactive isotope of hydrogen that future reactors would have to make on-site.

But most of these challenges aren’t unique to NIF, and the world’s many fusion labs and companies are chipping away at them. Last year the Joint European Torus (JET), an experimental reactor in Culham, England, set a record for the most fusion energy ever released during a single experimental run. Construction on JET’s successor— a huge international experiment known as ITER —is underway in France. And private companies in the United States and United Kingdom have built next-generation superconducting magnets, which could help create smaller, more powerful kinds of reactors.

It’s hard to say when, or even if, this work will yield a new energy future. But fusion researchers see the technology as an incredible tool for humankind whenever it’s ready—whether that’s 20, 50, or 100 years from now.

“When people say fusion is very complex, it’s true, but when people say that fusion is too complex, it’s not,” Fasoli says. “We know how to do complex things … Going to the moon is not simple. Achieving this result in fusion, it’s not simple. And we’ve demonstrated we can do it.”

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Scientists Achieve Nuclear Fusion Breakthrough With Blast of 192 Lasers

The advancement by Lawrence Livermore National Laboratory researchers will be built on to further develop fusion energy research.

By Kenneth Chang

Scientists studying fusion energy at Lawrence Livermore National Laboratory in California announced on Tuesday that they had crossed a long-awaited milestone in reproducing the power of the sun in a laboratory.

That sparked public excitement as scientists have for decades talked about how fusion, the nuclear reaction that makes stars shine, could provide a future source of bountiful energy.

The result announced on Tuesday is the first fusion reaction in a laboratory setting that actually produced more energy than it took to start the reaction.

“This is such a wonderful example of a possibility realized, a scientific milestone achieved, and a road ahead to the possibilities for clean energy,” Arati Prabhakar, the White House science adviser, said during a news conference on Tuesday morning at the Department of Energy’s headquarters in Washington, D.C. “And even deeper understanding of the scientific principles that are applied here.”

If fusion can be deployed on a large scale, it would offer an energy source devoid of the pollution and greenhouse gases caused by the burning of fossil fuels and the dangerous long-lived radioactive waste created by current nuclear power plants, which use the splitting of uranium to produce energy.

Within the sun and stars, fusion continually combines hydrogen atoms into helium, producing sunlight and warmth that bathes the planets. In experimental reactors and laser labs on Earth, fusion lives up to its reputation as a very clean energy source.

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June 1, 2023

15 min read

What Is the Future of Fusion Energy?

Nuclear fusion won’t arrive in time to fix climate change, but it could be essential for our future energy needs

By Philip Ball

L ast December physicists working on fusion claimed a breakthrough. A team at the National Ignition Facility (NIF) in California announced it had extracted more energy from a controlled nuclear fusion reaction than had been used to trigger it . It was a global first and a significant step for physics—but very far from enabling practical exploitation of fusion as an energy source. The high-profile announcement elicited a familiar pattern of responses to fusion research: acclaim from boosters of the technology and dismissals from skeptics, who complain that scientists continually promise that fusion is just 20 years away (or 30 or 50, take your pick).

These fervent reactions reflect the high stakes for fusion . The world is increasingly desperate for an abundant source of clean energy that can mitigate the climate crisis created by burning fossil fuels. Nuclear fusion—the merging of light atomic nuclei—has the potential to produce energy with near-zero carbon emissions, without creating the dangerous radioactive waste associated with today's nuclear fission reactors, which split the very heavy nuclei of radioactive elements. Physicists have been studying fusion power since the 1950s, but turning it into a practical energy source has remained frustratingly elusive. Will it ever be a significant source of power for our energy-hungry planet —and if so, will it arrive in time to save Earth from meltdown?

The latter question is one of the few in this field to which there is a clear answer. Most experts agree that we're unlikely to be able to generate large-scale energy from nuclear fusion before around 2050 (the cautious might add on another decade). Given that the global temperature rise over the current century may be largely determined by what we do—or fail to do—about carbon emissions before then, fusion can be no savior. (Observatory columnist Naomi Oreskes also makes this point here .) “I do think fusion looks a lot more plausible now than it did 10 years ago as a future energy source,” says Omar Hurricane, a program leader at Lawrence Livermore National Laboratory, where the NIF is housed. “But it's not going to be viable in the next 10 to 20 years, so we need other solutions.”

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Decarbonizing by mid-century will therefore depend on other technologies: renewables such as solar and wind; nuclear fission; and perhaps carbon-capture techniques. As we look further out, though, there are good reasons to think fusion will be a key part of the energy economy in the second half of the century, when more developing countries will start requiring Western-size energy budgets. And solving the problem of climate change is not a one-time affair. If we can navigate the bottleneck of the next few decades without transforming the climate too radically, the road beyond may be smoother.

The Long Haul

Nuclear fusion was recognized as a potential source of energy almost as soon as fission was. In a debriefing meeting of the Manhattan Project in late 1945, Italian physicist Enrico Fermi, who led the project to build the first fission reactor in Chicago during World War II, envisioned fusion reactors for power generation. Scientists figured out how to release fusion energy a few years later but only in the uncontrolled Armageddon-like explosions of hydrogen bombs. Once we learned how to conduct the process in a controlled and sustained manner, some scientists predicted, electricity would become “too cheap to meter.”

Credit: Mark Belan

But the challenges proved much greater than expected. “It's superhard,” Hurricane says. “We're basically making stars on Earth.” The fusion of two hydrogen atoms to make helium is the main process that powers the sun and other stars. When such light atomic nuclei combine, they release an immense amount of energy. But because these nuclei have positive electrical charges, they repel one another, and it takes tremendous pressures and temperatures to overcome that electrostatic barrier and get them to merge. If scientists can contain the fuel for fusion—a plasma mixture of deuterium and tritium, two heavy isotopes of hydrogen—the energy released in the reaction can make it self-sustaining. But how do you bottle a plasma at a temperature of around 100 million kelvins, several times hotter than the center of the sun?

No known material can withstand such extreme conditions; they would melt even extremely heat-resistant metals such as tungsten in an instant. The answer long favored for reactor design is magnetic confinement: holding the electrically charged plasma in a “magnetic bottle” formed by strong magnetic fields so it never touches the walls of the fusion chamber. The most popular design, called a tokamak and proposed in the 1950s by Soviet scientists, uses a toroidal (or doughnut-shaped) container.

The process requires exquisite control. The furiously hot plasma won't stay still: it tends to develop large temperature gradients, which generate strong convection currents that make the plasma turbulent and hard to manage. Such instabilities, akin to miniature solar flares, can bring the plasma into contact with the walls, damaging them. Other plasma instabilities can produce beams of high-energy electrons that bore holes in the reaction-chamber cladding. Suppressing or managing these fluctuations has been one of the key challenges for tokamak designers. “The big success of the past 10 years has been in understanding this turbulence in quantitative detail,” says Steven Cowley, who directs the Princeton Plasma Physics Laboratory.

One of the biggest obstacles to magnetic-confinement fusion is the need for materials that can withstand the tough treatment they'll receive from the fusing plasma. In particular, deuterium-tritium fusion makes an intense flux of high-energy neutrons, which collide with the nuclei of atoms in the metal walls and cladding, causing tiny spots of melting. The metal then recrystallizes but is weakened, with atoms shifted from their initial positions. In the cladding of a typical fusion reactor, each atom might be displaced about 100 times over the reactor's lifetime.

Plasma flows within the target chamber at the National Ignition Facility (NIF). Credit:  Lawrence Livermore National Laboratory

The consequences of such intense neutron bombardment aren't well understood, because fusion has never been sustained for the long periods that would be required in a working reactor. “We don't know and won't know about materials degradation and lifetime until we've operated a power plant,” says Ian Chapman, CEO of the U.K. Atomic Energy Authority (UKAEA), the British government's nuclear energy organization. Nevertheless, important insights into these degradation problems might be gleaned from a simple experiment that generates intense neutron beams that can be used to test materials. Such a facility—a particle-accelerator-based project called the International Fusion Materials Irradiation Facility–Demo Oriented Neutron Source—should begin operating in Granada, Spain, in the early 2030s. A similar U.S. facility called the Fusion Prototypic Neutron Source has been proposed but doesn't yet have approval.

There is still no guarantee that these material issues can be solved. If they prove insurmountable, one alternative is to make the reactor walls from liquid metal, which can't be damaged by melting and recrystallization. But that, Cowley says, brings in a whole suite of other technical concerns.

Another major challenge is making the fusion fuel. The world has abundant deuterium: this isotope constitutes 0.016 percent of natural hydrogen, so the seas are literally awash in it. But tritium forms only in small quantities naturally, and it decays radioactively with a half-life of just 12 years, so it's constantly disappearing and must be produced afresh. In principle, it can be “bred” from fusion reactions because the fusion neutrons will react with lithium to make it. Most reactor designs incorporate this breeding process by surrounding the reactor chamber with a blanket of lithium. All the same, the technology is unproven at large scales, and no one really knows whether or how well tritium production and extraction will work.

Gargantuan Machines

The largest fusion project in the world, ITER (Latin for “the way” and originally an acronym for “ International Thermonuclear Experimental Reactor ”) in southern France, will use a massive tokamak with a plasma radius of 6.2 meters; the entire machine will weigh 23,000 metric tons. If all goes to plan, ITER—supported by the European Union, the U.K., China, India, Japan, South Korea, Russia and the U.S.—will be the first fusion reactor to demonstrate continuous energy output at the scale of a power plant (about 500 megawatts, or MW). Construction began in 2007. The initial hope was that plasmas would be produced in the fusion chamber by about 2020, but ITER has suffered repeated delays while the estimated cost of $5.45 billion has quadrupled. This past January the project's leaders announced a further setback: the intended start of operation in 2035 may be delayed to the 2040s. ITER will not produce commercial power—as its name says, it is strictly an experimental machine intended to resolve engineering problems and prepare the way for viable power plants.

This new holdup of what some regard as a cumbersome behemoth with no guarantee of success prompted another bout of fusion skepticism. But such problems are to be expected, Hurricane says. “ITER is getting beaten up a lot, but we need to give them a break and let them sort out the problems,” he says.

Chapman agrees. “It was very predictable that there would be problems, both politically and technically,” he says. “The project is doing amazing things, including establishing supply chains that didn't exist before.” The delay is disappointing, he admits, “but I don't think we'll look back on ITER and think it was a mistake. We'll think it was really important in the genesis of fusion. I'm convinced it will work.”

Tokamaks for power plants will probably not need to be as gargantuan, and certainly cannot be as expensive, as ITER. Lately there has been increasing interest in smaller devices with a more spherical shape, like a cored apple. One of these, called the Spherical Tokamak for Energy Production (STEP), is being planned by the UKAEA as a pilot plant to be developed in parallel with ITER.

The spherical design concept had a successful proof-of-principle run with a device called the Mega Ampere Spherical Tokamak (MAST), which operated from 1999 to 2013, overseen by UKAEA and the European Atomic Energy Community (Euratom). These smaller machines have a higher energy density and thus a greater risk of heat damage, especially from the extraction of hot spent fuel in the “exhaust” system. An improved version—MAST Upgrade—turned on in 2020 and has been able to extract heat about 20 times more efficiently than the original. “That really does open the path to conceiving of a compact power plant,” Chapman says.

Enter STEP, which aims to be just that: a prototype plant that produces net electricity. It is still in the concept design phase, but already the U.K. government has moved to create bespoke regulation for the project—the first in the world for fusion—that eliminates the need for a conventional nuclear license. Leaders selected a site last October: a coal power station in northern England that ceased operating in March and is scheduled to be demolished in early 2024. The site already has a cooling water supply and connections to the national grid and railway system.

At the site of the International Thermonuclear Experimental Reactor (ITER), a poloidal field coil undergoes testing. Six of these ring-shaped magnets will steer plasma within the experiment. Credit: Alastair Philip Wiper

The E.U. is planning its own prototype plant, called the DEMOnstration Power Plant (DEMO), administered by the EUROfusion consortium and aiming to produce between 200 and 500 MW of electric power. Construction might begin in the early 2040s, says Tony Donné, EUROfusion's program manager. “I'm convinced we can build such a device in 10 years.”

Donné adds that there are equivalent “stepping stone” projects toward fusion plants in South Korea, Japan and China; the U.S. made plans for a smaller device called the Fusion Nuclear Science Facility. “China has come to the party a bit late but is now investing heavily and growing its workforce rapidly,” Chapman says. “It is definitely catching up with what already exists in Europe and the U.S.” Donné believes that some friendly competition—a kind of “moon race” for the first prototype fusion plant—could be beneficial as long as countries continue to share information.

The Start-up Scene

It's not all about big national and international projects. Small spherical tokamaks are one of the technologies that have brought fusion within the reach of private companies. Several dozen fusion start-ups have sprung up around the world, such as Commonwealth Fusion Systems (CFS) in Massachusetts, General Fusion in Canada, and Tokamak Energy in the U.K.

General Fusion, with support from the UKAEA, has just begun building a demonstration plant that it hopes (ambitiously) to have running by 2025. According to the company's former CEO Christofer Mowry, it will be “the first power-plant-relevant large-scale demonstration.” Meanwhile CFS, in partnership with the Plasma Science and Fusion Center (PSFC) of the Massachusetts Institute of Technology and others, is building a prototype device called SPARC, also targeted for completion in 2025. SPARC will be a midsize tokamak in which the plasma is tightly confined by very intense magnetic fields produced by new high-temperature superconducting magnets developed at M.I.T. and unveiled in 2021. Such magnets were hailed as a significant step for magnetic-confinement fusion because the power density in the plasma increases rapidly as the strength of the magnetic field rises.

The SPARC team aims to extract net energy from the plasma (about 10 times more energy out than in) and to generate 50 to 140 MW of fusion power. Although SPARC is much smaller than ITER, the PSFC's director, Dennis Whyte, says its mission is similar: to solve the science and technology problems that stand in the way of commercialization. It won't feed any energy into the grid, but it's meant to clear a path for the “affordable, robust, compact” fusion reactor concept developed at M.I.T. and pursued by CFS, which Cowley considers “the most impactful company” so far.

Cowley welcomes such projects but cautions against seeing them as a shortcut to making fusion a realistic energy source. “We see these start-up companies coming in with a lot of enthusiasm, and a lot of their focus is on a particular part of the problem,” he says. It's highly unlikely that one of them will make fusion energy commercial before the big guns, and many will simply fold—as some start-ups always do. But Chapman believes others will become valuable suppliers of expertise and of specialized components such as magnets. “Most of the small fusion companies will end up being part of the supply chain,” he says.

Different Designs

Setups for magnetic-confinement fusion are not necessarily limited to tokamaks. In the 1950s astrophysicist Lyman Spitzer argued that plasma might be contained more effectively in a doughnut chamber with a twisted tunnel wall. With this configuration, the device could keep the plasma constrained by using the magnetic fields generated by flows in the charged plasma itself.

The more complex geometry of this design, called a stellarator, is tricky to engineer, but a few projects are pursuing it. A notable example is the Wendelstein 7-X stellarator in Greifswald, Germany, completed in 2015 and now operating again after a three-year upgrade. “A stellarator has some advantages, but technically it's a more complicated device,” Donné says. “In Europe, we're working on the stellarator as a backup to the tokamak.” The technology is still at a relatively early stage, so if that backup turns out to be essential, the timescale for practical fusion is likely to be pushed back again.

The strategy at the NIF is totally different from all of these projects. Instead of using a large amount of plasma confined by magnetic fields, the NIF experiment ignites a tiny target of deuterium and tritium. In this case, the fusing plasma is held in place only fleetingly by its own inertia after the experiment triggers fusion by squeezing the fuel abruptly and heating it intensely—a scheme called inertial confinement fusion. The NIF produces these extreme conditions by focusing very intense laser beams on the pellet-shaped targets. The fusion energy is released in a brief burst before the hot plasma expands. This kind of energy production would therefore happen in pulses, and fuel capsules would have to be constantly moved one after another into the reaction chamber to be ignited. Most researchers estimate that for the approach to be practical, capsules would have to be replaced about 10 times a second.

The challenges for inertial confinement fusion are daunting, and at present only a few facilities in the world are studying it. Besides the NIF, the biggest, there are the Megajoule Laser facility in France and the Shenguang-III laser facility in China; Russia also might be pursuing this approach, but the details are hard to ascertain. Energy generation isn't actually a main part of the NIF mission; the facility was intended mostly to trigger nuclear reactions for studying and maintaining the U.S. stockpile of nuclear weapons . “The primary work at the NIF has been funded entirely by the U.S. national security apparatus,” Hurricane says. “It is not a fusion reactor and is not meant to demonstrate fusion energy in any practical sense.”

Much more work lies ahead to make inertial confinement fusion a true contender for supplying energy. “The work has focused on the fundamental science, and we haven't put as much effort into the supporting technologies needed for a power plant,” says Tammy Ma, who leads the NIF's inertial fusion energy initiative.

Looking Forward

Given this varied landscape of fusion projects, how close is practical fusion energy really? Chapman is blunt: “There is not today a single project underway to build a fusion power plant that will produce energy.”

And real power plants—ones that aren't just prototypes—take a decade or so to construct. “Experiments are making progress, and the progress is impressive,” Chapman says, “but fusion is not going to be working [as a source of mass energy] in a few years' time.” Donné is blunter still: “Anyone who tells me that they'll have a working future reactor in five or 10 years is either completely ignorant or a liar.”

Forecasting when fusion energy will arrive has always been a risky business, but experts now mostly agree on the approximate timescales. “Suppose we get a pilot plant that works by the end of the 2030s, although that would be going some,” Cowley says. Such a plant is unlikely to be a blueprint for commercialization, and so, he says, “I think you'd have another stage of about 10 years from a pilot plant to the first commercial reactor.” Chapman concurs that fusion plants might be feeding power into the grid by around 2050 and then could become steadily more important to the energy economy in the second half of the century, especially post-2060.

Fusion plants are likely to be of about the same scale as today's fossil-fuel or fission plants, with outputs of a few gigawatts. That means they could be constructed on the same sites, replacing like with like, and with all the necessary electrical-grid infrastructure already in place. “You could say that fusion is very easy to plug in and replace either fossil fuels or fission,” Donné says. “This can be a very smooth transition.” He expects that fusion plants will replace first the still active coal plants, then oil and gas, and finally fission.

A segment of the twisted vessel for plasma at the Wendelstein 7-X stellarator fusion experiment. Credit:  Wolfgang Filser, MPI for Plasma Physics

Even if fusion can't save us from the immediate climate crisis, over the long term it may be the best option to satisfy our energy needs without destroying the planet. Soviet fusion visionary Lev Artsimovich, the “father of the tokamak,” once said that the world will have nuclear fusion when it decides it needs it. “When we realize what climate change will do as an existential threat, the delivery of fusion will accelerate enormously,” Chapman says, drawing an analogy to the quick development of COVID-19 vaccines. At the moment we simply have no other long-term way of getting to net-zero carbon emissions, especially because the global energy demand is projected to triple between 2050 and 2100. “Fusion is essential” to meet that need, Chapman says. “I can't see what else it will be.” Renewables such as wind and solar energy definitely have a role to play, Donné says, but they aren't likely to be enough.

Building a new kind of energy infrastructure from the ground up presents opportunities as well as challenges. Nuclear fission planners made some serious mistakes in terms of design and public relations, but now the nascent fusion industry has a chance to learn from those mistakes and do better—not least by thinking about issues of energy equity and justice. “When we have these plants, where do we place them so that we can provide a clean energy source for all types of communities?” the NIF's Ma asks. “How do we build up a workforce that is diverse? How do we ensure that as we are building up this industry, we are training folks to have the skills of the future? We get to at least try to do it right this time.”

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Participants at the side event on latest advances in research and development in fusion technology. (Photo: J. C. Castillo/IAEA)

Scientists are becoming increasingly excited about the prospects that within the foreseeable future a reactor can replicate the sun’s energy source on Earth through scientific and technological innovation of a scale previously unimagined. During the annual IAEA General Conference, a side event on nuclear fusion technology was held to discuss latest advances in research and development in fusion technology.

“The world is getting warmer with emissions getting from bad to worse, it is hopeful that alternative sources of energy such as fusion technology can provide electricity worldwide by the middle of this century,” said Steve Cowley, Director of the Culham Centre for Fusion Energy in the United Kingdom, in his introductory remarks.

He also highlighted the pioneering work of the IAEA in promoting international collaboration in this field since 1958 and without this support, the development of fusion technology would be further behind. “We now need to urgently ramp up the work going on at the International Thermonuclear Experimental Reactor (ITER) and to push the experiment forward to meet the growing energy demands.”

Discussions provided insights into the status of fusion research presently and possibilities for its upscaling to commercial energy production. Global collaboration was the best way forward to close the technological and scientific gaps to realize the dream of a functioning fusion power plant within the foreseeable future, panelists agreed.

“It is too expensive and technologically challenging to attempt charting a lonely research path,” Richard Kamendje, a fusion physicist at the IAEA, told the audience. “Therefore the role played by the IAEA in fostering international collaboration and facilitating the exchange of scientific and technical information in the fusion field is key for its success.”

Global Experiment aims to harnessing fusion energy

The challenge to create a source of energy similar to that of the sun itself in a reactor is yet to be conquered. With dedicated research and unprecedented international collaboration, scientists believe that there is light at the end of the tunnel to re-create this energy in a reactor that can deliver energy to the electricity grid.

This innovative experiment is to be carried out at a global nuclear fusion experiment facility presently under construction. Known as ITER and located in Cadarache, in the south of France; it is an international project with seven members: China, India, Japan, South Korea, the European Union, the Russian Federation and the United States.

“There are so many international partners who are working on the components and manufacturing areas of the ITER project,” said Cowley. “Though we may compete in the advances made at the national level in fusion science and technology, we gain from the constructive outcomes. The competition to find the solutions to a problem benefits the goals of ITER. Fusion prototype reactors are being built at the national level, but what is also motivating scientists like us, is the global eagerness to see an end result that is positive for humanity.”

The ITER experiment boldly represents the magic of international collaboration for the peaceful uses of the atom. ITER, should the experiment succeed, would show the path to building a power plant that uses controlled nuclear fusion, as a potentially inexhaustible energy source. More significantly, it will demonstrate how the greatest of challenges in modern science and technology can be successfully overcome through international cooperation.

Giving an overview of the current status of the project and the challenges, David Campbell, Director of the Science and Operations Department at ITER pointed out that this project is the largest international scientific collaboration on earth to create sustainable energy. “From the delivery of large plant components for the experimental reactor to building additional support structures, are among some of the challenges we are facing. Without international collaboration and support, this project would just not be possible.”

Proponents of fusion technology are also aiming for commercial utilization, and this on-going experiment needs to speed up, move ahead as rapidly as possible to make ITER operational at the earliest, he reiterated.

The theory is relatively straight forward. The nuclear fusion reactor should achieve self-sustaining fusion reactions and produce in excess of several hundreds of MW of fusion power. But turning science to practical application is complex and challenging. While the ITER facility will test key technologies necessary for a fusion reactor, many countries are independently initiating new research and development activities leading to a demonstration of fusion energy’s readiness for commercialization (DEMO). But it would all come together, in the spirit of international collaboration under a world “DEMO Programme.”  The IAEA organizes a series of DEMO programme workshops to facilitate and strengthen international cooperation to define and coordinate DEMO programme activities.

Scientists and policy makers are convinced that we are on the edge of an ‘Age of Fusion’ and the ITER facility and demonstration plants would establish the technology to significantly meet, in the not too distant future, humanity’s energy needs through a virtually inexhaustible, safe, environmentally-friendly and universally-available resource.

The IAEA has been in the forefront of nuclear fusion research efforts since the 1950s. The IAEA has focused its efforts on facilitating the coordination of international fusion undertakings and enhancing the interaction among developing Member States with leading fusion initiatives. The Agency can rightfully claim its share of credit in supporting the pioneering ways to make fusion energy a reality for meeting the global energy demand. 

We now need to urgently ramp up the work going on at the International Thermonuclear Experimental Reactor (ITER) and to push the experiment forward to meet the growing energy demands. Steve Cowley, Director, Culham Centre for Fusion Energy, the United Kingdom

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Nuclear fusion breakthrough: Decades of research are still needed before fusion can be used as clean energy

Assistant Professor, Mechanical and Aerospace Engineering, Carleton University

Disclosure statement

Kristen Schell receives funding from NSERC, ECCC and the US Department of Energy.

Ahmed Abdulla receives funding from NSERC, ECCC and Carleton University

Carleton University provides funding as a member of The Conversation CA.

Carleton University provides funding as a member of The Conversation CA-FR.

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The U.S. Department of Energy reported a major scientific breakthrough in nuclear fusion science in December 2022. For the first time, more energy was released from a fusion reaction than was used to ignite it.

While this achievement is indeed historic, it’s important to pause and reflect on the way ahead for fusion energy.

We are professors of sustainable and renewable energy engineering at Carleton University, where we research alternative energy technologies and systems that can move us to a low-carbon future.

We also teach our students how to navigate the treacherous terrain from lab-based findings to real-world applications.

Defining system boundaries

The efficiency of a potential fusion energy power plant remains to be seen. The reported fusion net gain actually required about 300 megajoules of energy input , which was not included in the energy gain calculation. This energy input, needed to power 192 lasers , came from the electric power grid.

In other words, the experiment used as much energy as the typical Canadian household does in two days. In doing so, the fusion reaction output enough energy to light just 14 incandescent bulbs for an hour.

The same is true of nuclear fission, which is the reaction inside current nuclear power plants. The complete fission of one kilogram of Uranium-235 — the fissile component of nuclear fuel — can generate about 77 terajoules . But we cannot convert all of that energy into useful forms like heat and electric power.

Instead, we have to engineer a complex system that can control the nuclear fission chain reaction and convert the generated energy into more useful forms.

This is what nuclear power plants do — they harness the heat generated during nuclear fission reactions to make steam. This steam drives a turbine connected to an electric power generator, which produces electricity. The overall efficiency of the cycle is less than 40 per cent.

In addition, not all of the uranium in the fuel is burned. Used fuel still contains about 96 per cent of its total uranium, and about a fifth of its fissile Uranium-235 content.

Increasing the amount of uranium spent in our current fleet is possible — it’s an ongoing sphere of work — but it poses enormous engineering challenges. The huge energy potential of nuclear fuel is currently mitigated by the engineering challenges of converting that energy into a useful form.

From science to engineering

Until recently, fusion has been seen primarily as a scientific experiment, not as an engineering challenge. This is rapidly changing and regulators are now investigating how deployment might unfold in the real world.

Regardless of the efficiency of a future fusion power plant, taking energy conversions from basic science to the real world will require overcoming a multitude of challenges.

Because fission faced many of the same challenges as fusion now does, we can learn a lot from its history. Fission also had to move from science to engineering before the commercial industry could take off.

The science of fusion energy, as with nuclear fission, is rooted in efforts to develop nuclear weapons. Notably, several nuclear physicists who helped develop the nuclear bomb wanted to “ prove that this discovery was not just a weapon .”

The early history of nuclear power was one of optimism — of declarations the technology would advance and be able to meet our need for ever-increasing amounts of energy. Eventually, fusion power would come along and electricity would become “too cheap to meter.”

Lessons learned

What have we learned over the past 70 years since the onset of nuclear power? First, we’ve learned about the potentially devastating risk of technology lock-in , which occurs when an industry becomes dependent on a specific product or system.

Today’s light-water fission reactors — reactors that use normal water as opposed to water enriched with a hydrogen isotope — are an example of this. They were not chosen because they were the most desirable, but for other reasons.

These factors include government subsidies that favoured these designs; the U.S. Navy’s interest in developing smaller-scale pressurized water reactors for submarines and surface warships; advances in uranium enrichment technology as a result of the U.S. nuclear weapons program; uncertainties regarding nuclear costs that led to the assumption that large light-water reactors are simply scaled-up versions of smaller ones; and conservatism regarding design choices given the high costs and risks associated with nuclear power development.

We have been struggling to move to other technologies ever since.

Second, we’ve learned that size matters. Large reactors cost more to build per unit of capacity than smaller units. In other words, engineers misunderstood the concept of economies of scale and doomed their industry in the process.

Large infrastructure projects are extremely complex systems that rely on enormous work forces and co-ordination. They can be managed, but they usually go over-budget and fall behind schedule. Modular technologies exhibit better affordability , cost control and economies, but micro and small nuclear reactors will also be economically challenged.

Third, regulatory regimes must be developed for fusion. If the industry coalesces too quickly around a first-generation design, the consequences for the regulation of future reactors could be severe.

Fourth, choosing locations for new power plants and societal acceptance are key. Fusion has an advantage because its technology is more of a blank slate than fission when it comes to public opinion. The positive associations the public has with fusion must be maintained by prudent design decisions and adopting best practices for community engagement .

The same is true of how the industry will choose to handle the waste challenge. Fusion reactors generate large amounts of waste, though not the same kind fission does .

A call to action

Our research on nuclear energy innovation reveals that challenges facing nuclear fusion can be overcome, but they require prudent leadership, decades of research, significant amounts of funding and focus on technology development.

Billions of dollars are needed to advance nuclear fission technology, and we have far more experience with fission than with fusion. An appetite for funding must be demonstrated by governments, electric utility companies and entrepreneurs.

Fusion’s promise is vast and there is exciting work being done to advance it outside of this recent breakthrough, including by private companies . Decades of research and development are needed before fusion can meaningfully contribute to our energy system.

Our central message is a call to action: fusion engineers, researchers, industry and government must organize to investigate and mitigate the challenges that face fusion, including in the design of the first generation of power plants.

There is no substitute to deep and rapid decarbonization of the energy system if we want to save our planet from climate catastrophe. We are proud to be training the next generation of energy engineers to design new and better energy solutions.

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December 15, 2022

Nuclear fusion: how scientists can turn latest breakthrough into a new clean power source

by John Pasley, The Conversation

Researchers in the US have finally fulfilled an objective that was set decades ago: the achievement of "ignition"—getting more energy out than you put in—using nuclear fusion.

The scientists at the Lawrence Livermore National Laboratory 's National Ignition Facility (NIF), where the experiment took place, are no doubt both excited and relieved to finally fulfil the promise implied by the name of their facility. But how excited should the rest of us be? What does this really mean for the possibility of creating effectively unlimited amounts of clean energy, and what else needs to happen to achieve this?

While the fusion reactions released more energy that was put in to the target, this doesn't take into account the far greater quantities of energy needed to fire the laser that was used to drive the experiment. Also the burst of energy was not in the form of electricity, but a pulse of energetic particles. Harnessing those particles to produce electricity—and keeping a fusion reactor running constantly—will entail overcoming many hurdles.

Nevertheless, ignition is a remarkable achievement, and one which promises to stimulate interest in, and possibly also leverage funds for, tackling these further challenges.

The experiment: how it worked and what it achieved

Let's take a look at the details of exactly has been achieved. The researchers used a high-power laser to fire 2.05 million Joules of energy into a tiny target containing fusion fuel. This forced light atomic nuclei in the fuel together to create heavier nuclei— releasing 3.15 million Joules of energy in the process.

This corresponds to a gain of around 1.5 (2.05 x 1.5 = 3.1). It was a burst of energy so intense that, for a split second, burning fusion fuel produced ten thousand times more power than the combined output of every power station on Earth.

This is big science. The NIF building comprises not one but 192 individual laser beams, which bounce back-and-forth over a distance of more than a kilometre before they reach the target. The building which houses all of this tech is ten storeys high and the size of three (American) football pitches laid side by side.

Research into fusion falls into two main strands: laser driven fusion and magnetic confinement fusion . Magnetic confinement involves levitating fusion fuel in the form of a plasma (charged gas) using a large magnetic field.

Laser-driven fusion instead involves imploding tiny capsules of fusion fuel to incredibly high densities, at which point the burn will proceed so rapidly that significant energy can be released before the fuel has had chance to fly apart.

In both cases, the fuel must be raised to temperatures of tens of millions of degrees Celsius to start it burning. It is this requirement, more than any other, that makes fusion so difficult to achieve.

Laser-driven fusion still poses major challenges

Laser fusion is a pulsed technology, and a huge hurdle is the so-called laser repetition rate. Energy is released in intense bursts lasting much less than a billionth of a second, which must be repeated a few times every second to produce an average power output comparable to modern fossil-fuel based power stations.

The NIF laser by these standards is far too slow. It can be fired only twice a day. But NIF's goal was to demonstrate that ignition is possible on a single-shot basis, not to mimic the requirements of an actual power station.

Another reason that ignition took so long is that it is not NIF's only mission—it also supports the US nuclear weapons programme.

The physics of laser-driven fusion is so complex and multifaceted that computer simulations of it often take more time than actual experiments. Early on, modellers were more often learning from the experiments rather than telling the experimenters what to do next. An increasing closeness between model prediction and experimental outcome has underpinned the recent success at NIF and bodes well for future improvements in target design.

In the next few months, modellers and experimenters will need to show that the result can be reproduced—achieved again—something that has proven difficult in the past.

There are a number of other challenges to be tackled too. Considerable work has been done on designing and constructing lasers that can fire high energy pulses many times a second.

Another major limitation is that the NIF laser requires 300 million Joules of electrical input to provide two million Joules of laser light output—less than 1% efficiency. So the target would have to produce an unfeasibly large gain in order to produce more energy than went into powering the laser used in this instance.

However, the NIF laser is based on technologies that hark back to the 1980s. It uses flash lamps and amplifiers made from slabs of glass doped with the rare-earth element neodymium.

Modern high-power lasers using semiconductor technology can do far better, reaching around 20% efficiency. Given that laser-driven fusion targets are expected to be able to produce gains in excess of 100 when working optimally, using modern lasers would produce significant net energy output.

Building a working reactor is still some way off

Another challenge for laser-driven fusion is bringing down the cost of the targets. The manpower involved in making the NIF targets means that each one costs as much as a brand new car.

A new target is required every time the laser fires. For actual power production, this would mean a new one several times a second. The targets used on NIF also rely on a technique known as "indirect drive" in which the target first converts the laser energy into X-rays that then implode the fusion fuel capsule inside the target. This adds both complexity and cost.

Many scientists consider that the way forward for laser-driven fusion energy would involve "direct drive" ignition . Here, the laser directly illuminates a simple, spherical fuel capsule. This approach to ignition has, however, yet to be demonstrated.

NIF's fuel (deuterium and tritium) gives out much of its energy in the form of high-energy neutrons (particles which make up the atomic nucleus along with protons). The neutrons interact with the materials in the reactor vessel, changing their composition and microscopic structure.

This could pose serious challenges for optical components that must transmit or reflect laser light efficiently. Some scientists consider driving similar physics by alternative means , perhaps using pulsed electrical power directly, or focused beams of ions (charged atoms).

Magnetic confinement fusion research leads the way in many areas related to constructing a power reactor. It has had to tackle many of the same problems in order to design and build the ITER facility , which also aims to produce gain and is nearing completion in the south of France. Scientists and engineers from the two strands of research collaborate on aspects related to reactor construction which are common to both fields.

Fusion power has, for decades, seemed to be a prize that remains forever just out of reach. Though significant challenges remain, as researchers are now actively working on improving laser technology and reactor design, breakthroughs will inevitably lead to further progress towards nuclear fusion based power plants. Some researchers working on fusion are now sensing that they might see fusion providing energy to the grid within their own lifetimes.

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nuclear fusion , process by which nuclear reactions between light elements form heavier elements (up to iron ). In cases where the interacting nuclei belong to elements with low atomic numbers (e.g., hydrogen [atomic number 1] or its isotopes deuterium and tritium ), substantial amounts of energy are released. The vast energy potential of nuclear fusion was first exploited in thermonuclear weapons , or hydrogen bombs , which were developed in the decade immediately following World War II . For a detailed history of this development, see nuclear weapon . Meanwhile, the potential peaceful applications of nuclear fusion, especially in view of the essentially limitless supply of fusion fuel on Earth , have encouraged an immense effort to harness this process for the production of power . For more detailed information on this effort, see fusion reactor .

This article focuses on the physics of the fusion reaction and on the principles of achieving sustained energy-producing fusion reactions.

The fusion reaction

Fusion reactions constitute the fundamental energy source of stars, including the Sun . The evolution of stars can be viewed as a passage through various stages as thermonuclear reactions and nucleosynthesis cause compositional changes over long time spans. Hydrogen (H) “burning” initiates the fusion energy source of stars and leads to the formation of helium (He). Generation of fusion energy for practical use also relies on fusion reactions between the lightest elements that burn to form helium. In fact, the heavy isotopes of hydrogen— deuterium (D) and tritium (T)—react more efficiently with each other, and, when they do undergo fusion, they yield more energy per reaction than do two hydrogen nuclei. (The hydrogen nucleus consists of a single proton . The deuterium nucleus has one proton and one neutron , while tritium has one proton and two neutrons.)

Fusion reactions between light elements, like fission reactions that split heavy elements, release energy because of a key feature of nuclear matter called the binding energy , which can be released through fusion or fission. The binding energy of the nucleus is a measure of the efficiency with which its constituent nucleons are bound together. Take, for example, an element with Z protons and N neutrons in its nucleus. The element’s atomic weight A is Z + N , and its atomic number is Z . The binding energy B is the energy associated with the mass difference between the Z protons and N neutrons considered separately and the nucleons bound together ( Z + N ) in a nucleus of mass M . The formula is B = ( Z m p + N m n − M ) c 2 , where m p and m n are the proton and neutron masses and c is the speed of light . It has been determined experimentally that the binding energy per nucleon is a maximum of about 1.4 10 −12 joule at an atomic mass number of approximately 60—that is, approximately the atomic mass number of iron . Accordingly, the fusion of elements lighter than iron or the splitting of heavier ones generally leads to a net release of energy.

Fusion reactions are of two basic types: (1) those that preserve the number of protons and neutrons and (2) those that involve a conversion between protons and neutrons. Reactions of the first type are most important for practical fusion energy production, whereas those of the second type are crucial to the initiation of star burning. An arbitrary element is indicated by the notation A Z X , where Z is the charge of the nucleus and A is the atomic weight. An important fusion reaction for practical energy generation is that between deuterium and tritium (the D-T fusion reaction). It produces helium (He) and a neutron ( n ) and is written D + T → He + n .

To the left of the arrow (before the reaction) there are two protons and three neutrons. The same is true on the right.

The other reaction, that which initiates star burning, involves the fusion of two hydrogen nuclei to form deuterium (the H-H fusion reaction): H + H → D + β + + ν, where β + represents a positron and ν stands for a neutrino . Before the reaction there are two hydrogen nuclei (that is, two protons). Afterward there are one proton and one neutron (bound together as the nucleus of deuterium) plus a positron and a neutrino (produced as a consequence of the conversion of one proton to a neutron).

Both of these fusion reactions are exoergic and so yield energy. The German-born physicist Hans Bethe proposed in the 1930s that the H-H fusion reaction could occur with a net release of energy and provide, along with subsequent reactions, the fundamental energy source sustaining the stars. However, practical energy generation requires the D-T reaction for two reasons: first, the rate of reactions between deuterium and tritium is much higher than that between protons; second, the net energy release from the D-T reaction is 40 times greater than that from the H-H reaction.

New fusion reactor design promises unprecedented plasma stability

Novatron’s atm design, merging magnetic mirrors and biconic cusps, seeks to achieve stable plasma..

Aman Tripathi

Novatron's reactor overcomes fusion's stability and confinement hurdles. (Representational image)

FFE    

Novatron, a private fusion energy company, is making big strides in the clean energy arena with its innovative technology.

Researchers and institutions across the world are working on successfully achieving nuclear fusion, the process which powers the sun, on the Earth. However, achieving a controlled and sustained fusion reaction has yet to be realized.

It is in this context that Novatron is pushing boundaries of the nuclear fusion field with its groundbreaking axisymmetric tandem mirror (ATM) technology, which was recently unveiled.

“The new innovative Novatron reactor design is a new solution for stable plasma confinement and a significant step towards fusion power generation,” says the company.

Magnetic mirror concept

Novatron’s reactor is built upon the concept of a magnetic mirror machine.

These machines use two large magnets to trap the plasma fuel within a strong magnetic field, bouncing them back and forth like a ball in a mirror-lined room.

Magnetic mirrors have several appealing characteristics, including low cost, easy fueling, and the ability to operate continuously.

They also achieve a high “beta,” meaning they can produce high plasma pressure with relatively weak magnetic fields, which is more cost-effective.

However, traditional magnetic mirrors have two major drawbacks: they are prone to instabilities (the plasma tends to escape the trap) and have poor confinement time (they can’t hold the plasma for long).

Both stability and confinement time are crucial for achieving fusion, as the plasma needs to be hot and dense enough for long enough for fusion reactions to occur.

Balancing challenges

Novatron tackles these challenges by developing the ATM, a novel design combining magnetic mirrors with another concept called “biconic cusps.”

Magnetic mirrors utilize strong magnetic fields to confine plasma, the superheated matter where fusion occurs. Biconic cusps, on the other hand, provide stability to the plasma .

By integrating these concepts, Novatron’s ATM achieves both good confinement and inherent stability, overcoming key obstacles that have plagued traditional fusion approaches.

“The result is that the super-hot plasma strives to reach its inherently stable equilibrium in the center of the reactor, creating a stable process that can operate continuously,” highlighted Novatron.

Validation through simulations

Notably, the company has conducted extensive computer simulations to test its technology.

“We have performed extensive computer verification and stress-test simulations to confirm that the Novatron will perform as expected in real-world conditions,” says the company.

These simulations, conducted using the WarpX platform, have validated the stability of the ATM and demonstrated a remarkable improvement in energy confinement time.

“Our calculations have also indicated that we will have an energy confinement time improvement of a factor of 100 over traditional magnetic mirror machines,” Erik Oden, the company’s co-founder and chairman, told Computer Weekly .

Charting the course

Interestingly, the company has planned to achieve full commercial fusion power in stages.

“The Novatron fusion concept will be developed in four steps, with the final goal being a commercial fusion power plant design, ready to provide power to the energy grid,” concluded the company.

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More durable metals for fusion power reactors

Mit researchers have found a way to make structural materials last longer under the harsh conditions inside a fusion reactor..

Nancy W. Stauffer | MIT Energy Initiative

Based on theoretical and experimental studies, MIT engineers have shown that adding nanoparticles of certain ceramics to the metal walls of the vessel containing the reacting plasma inside a nuclear fusion reactor can protect the metal from damage, significantly extending its lifetime. Professor Ju Li (right) and postdoc So Yeon Kim (left) examine samples of the composite they have fabricated for their demonstrations.

Photo: Gretchen Ertl

For many decades, nuclear fusion power has been viewed as the ultimate energy source. A fusion power plant could generate carbon-free energy at a scale needed to address climate change. And it could be fueled by deuterium recovered from an essentially endless source — seawater.

Decades of work and billions of dollars in research funding have yielded many advances, but challenges remain. To Ju Li, the TEPCO Professor in Nuclear Science and Engineering and a professor of materials science and engineering at MIT, there are still two big challenges. The first is to build a fusion power plant that generates more energy than is put into it; in other words, it produces a net output of power. Researchers worldwide are making progress toward meeting that goal.

The second challenge that Li cites sounds straightforward: “How do we get the heat out?” But understanding the problem and finding a solution are both far from obvious.

Research in the MIT Energy Initiative (MITEI) includes development and testing of advanced materials that may help address those challenges, as well as many other challenges of the energy transition. MITEI has multiple corporate members that have been supporting MIT’s efforts to advance technologies required to harness fusion energy.

The problem: An abundance of helium, a destructive force

Key to a fusion reactor is a superheated plasma — an ionized gas — that’s reacting inside a vacuum vessel. As light atoms in the plasma combine to form heavier ones, they release fast neutrons with high kinetic energy that shoot through the surrounding vacuum vessel into a coolant. During this process, those fast neutrons gradually lose their energy by causing radiation damage and generating heat. The heat that’s transferred to the coolant is eventually used to raise steam that drives an electricity-generating turbine.

The problem is finding a material for the vacuum vessel that remains strong enough to keep the reacting plasma and the coolant apart, while allowing the fast neutrons to pass through to the coolant. If one considers only the damage due to neutrons knocking atoms out of position in the metal structure, the vacuum vessel should last a full decade. However, depending on what materials are used in the fabrication of the vacuum vessel, some projections indicate that the vacuum vessel will last only six to 12 months. Why is that? Today’s nuclear fission reactors also generate neutrons, and those reactors last far longer than a year.

The difference is that fusion neutrons possess much higher kinetic energy than fission neutrons do, and as they penetrate the vacuum vessel walls, some of them interact with the nuclei of atoms in the structural material, giving off particles that rapidly turn into helium atoms. The result is hundreds of times more helium atoms than are present in a fission reactor. Those helium atoms look for somewhere to land — a place with low “embedding energy,” a measure that indicates how much energy it takes for a helium atom to be absorbed. As Li explains, “The helium atoms like to go to places with low helium embedding energy.” And in the metals used in fusion vacuum vessels, there are places with relatively low helium embedding energy — namely, naturally occurring openings called grain boundaries.

Metals are made up of individual grains inside which atoms are lined up in an orderly fashion. Where the grains come together there are gaps where the atoms don’t line up as well. That open space has relatively low helium embedding energy, so the helium atoms congregate there. Worse still, helium atoms have a repellent interaction with other atoms, so the helium atoms basically push open the grain boundary. Over time, the opening grows into a continuous crack, and the vacuum vessel breaks.

That congregation of helium atoms explains why the structure fails much sooner than expected based just on the number of helium atoms that are present. Li offers an analogy to illustrate. “Babylon is a city of a million people. But the claim is that 100 bad persons can destroy the whole city — if all those bad persons work at the city hall.” The solution? Give those bad persons other, more attractive places to go, ideally in their own villages.

To Li, the problem and possible solution are the same in a fusion reactor. If many helium atoms go to the grain boundary at once, they can destroy the metal wall. The solution? Add a small amount of a material that has a helium embedding energy even lower than that of the grain boundary. And over the past two years, Li and his team have demonstrated — both theoretically and experimentally — that their diversionary tactic works. By adding nanoscale particles of a carefully selected second material to the metal wall, they’ve found they can keep the helium atoms that form from congregating in the structurally vulnerable grain boundaries in the metal.

Looking for helium-absorbing compounds

To test their idea, So Yeon Kim ScD ’23 of the Department of Materials Science and Engineering and Haowei Xu PhD ’23 of the Department of Nuclear Science and Engineering acquired a sample composed of two materials, or “phases,” one with a lower helium embedding energy than the other. They and their collaborators then implanted helium ions into the sample at a temperature similar to that in a fusion reactor and watched as bubbles of helium formed. Transmission electron microscope images confirmed that the helium bubbles occurred predominantly in the phase with the lower helium embedding energy. As Li notes, “All the damage is in that phase — evidence that it protected the phase with the higher embedding energy.”

Having confirmed their approach, the researchers were ready to  search  for helium-absorbing compounds that would work well with iron, which is often the principal metal in vacuum vessel walls. “But calculating helium embedding energy for all sorts of different materials would be computationally demanding and expensive,” says Kim. “We wanted to find a metric that is easy to compute and a reliable indicator of helium embedding energy.”

They found such a metric: the “atomic-scale free volume,” which is basically the maximum size of the internal vacant space available for helium atoms to potentially settle. “This is just the radius of the largest sphere that can fit into a given crystal structure,” explains Kim. “It is a simple calculation.” Examination of a series of possible helium-absorbing ceramic materials confirmed that atomic free volume correlates well with helium embedding energy. Moreover, many of the ceramics they investigated have higher free volume, thus lower embedding energy, than the grain boundaries do.

However, in order to identify options for the nuclear fusion application, the screening needed to include some other factors. For example, in addition to the atomic free volume, a good second phase must be mechanically robust (able to sustain a load); it must not get very radioactive with neutron exposure; and it must be compatible — but not too cozy — with the surrounding metal, so it disperses well but does not dissolve into the metal. “We want to disperse the ceramic phase uniformly in the bulk metal to ensure that all grain boundary regions are close to the dispersed ceramic phase so it can provide protection to those regions,” says Li. “The two phases need to coexist, so the ceramic won’t either clump together or totally dissolve in the iron.”

Using their analytical tools, Kim and Xu examined about 50,000 compounds and identified 750 potential candidates. Of those, a good option for inclusion in a vacuum vessel wall made mainly of iron was iron silicate.

Experimental testing

The researchers were ready to examine samples in the lab. To make the composite material for proof-of-concept  demonstrations , Kim and collaborators dispersed nanoscale particles of iron silicate into iron and implanted helium into that composite material. She took X-ray diffraction (XRD) images before and after implanting the helium and also computed the XRD patterns. The ratio between the implanted helium and the dispersed iron silicate was carefully controlled to allow a direct comparison between the experimental and computed XRD patterns. The measured XRD intensity changed with the helium implantation exactly as the calculations had predicted. “That agreement confirms that atomic helium is being stored within the bulk lattice of the iron silicate,” says Kim.

To follow up, Kim directly counted the number of helium bubbles in the composite. In iron samples without the iron silicate added, grain boundaries were flanked by many helium bubbles. In contrast, in the iron samples with the iron silicate ceramic phase added, helium bubbles were spread throughout the material, with many fewer occurring along the grain boundaries. Thus, the iron silicate had provided sites with low helium-embedding energy that lured the helium atoms away from the grain boundaries, protecting those vulnerable openings and preventing cracks from opening up and causing the vacuum vessel to fail catastrophically.

The researchers conclude that adding just 1 percent (by volume) of iron silicate to the iron walls of the vacuum vessel will cut the number of helium bubbles in half and also reduce their diameter by 20 percent — “and having a lot of small bubbles is OK if they’re not in the grain boundaries,” explains Li.

Thus far, Li and his team have gone from computational studies of the problem and a possible solution to experimental demonstrations that confirm their approach. And they’re well on their way to commercial fabrication of components. “We’ve made powders that are compatible with existing commercial 3D printers and are preloaded with helium-absorbing ceramics,” says Li. The helium-absorbing nanoparticles are well dispersed and should provide sufficient helium uptake to protect the vulnerable grain boundaries in the structural metals of the vessel walls. While Li confirms that there’s more scientific and engineering work to be done, he, along with Alexander O'Brien PhD ’23 of the Department of Nuclear Science and Engineering and Kang Pyo So, a former postdoc in the same department, have already developed a startup company that’s ready to 3D print structural materials that can meet all the challenges faced by the vacuum vessel inside a fusion reactor.

This research was supported by Eni S.p.A. through the MIT Energy Initiative. Additional support was provided by a Kwajeong Scholarship; the U.S. Department of Energy (DOE) Laboratory Directed Research and Development program at Idaho National Laboratory; U.S. DOE Lawrence Livermore National Laboratory; and Creative Materials Discovery Program through the National Research Foundation of Korea.

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Since the 1950s, international cooperation has been the driving force behind fusion research. Here, we discuss how the International Atomic Energy Agency has shaped the field and the events that have produced fusion’s global signature partnership.

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Cockroft, J. D. Nature 182 , 903–905 (1958).

Article   ADS   Google Scholar  

Dolgovsaveliev, G. G., et al. In Proc. 2nd Int. Conf. Geneva 82–91 (1958).

Spitzer, L. Phys. Fluids 1 , 253–264 (1958).

Article   ADS   MathSciNet   Google Scholar  

Interoffice memorandum from DDG Hubert de Laboulaye to DG Sterling Cole. IAEA Archives (IAEA, 1958).

Spitzer, L., Jr. In P r o c. 2nd Int. Conf. C ulham 3–11 (IAEA, 1966).

Artsimovich, L. A. In Proc. 3rd Int. Conf. Novosibirsk 11–17 (IAEA, 1969).

Peacock, N. J. et al. Nature 224 , 488–490 (1969).

Letter from Henry Seligman to Rendel Pease. IAEA Archives (IAEA, 1970).

Graves, G. A. Final report of the IAEA Panel on international cooperation in controlled fusion research and its application. Nucl. Fusion 10 , 413–421 (1970).

Article   Google Scholar  

Flakus, F. N. At. Energy Rev. 13 , 587–614 (1975).

Google Scholar  

Fusion Safety IAEA-TECDOC-277 (IAEA, 1983).

Fusion Safety Status Report IAEA-TECDOC-388 (IAEA, 1986).

Fusion Reactor Safety IAEA-TECDOC-440 (IAEA, 1987).

Spano, A. H. & Belozerov, A. Nucl. Fusion 14 , 281–283 (IAEA, 1974).

Conn, R. W. et al. Nucl. Fusion 18 , 985–1016 (1978).

INTOR, Group Nucl. Fusion 20 , 349–388 (1980).

Wagner, F. Phys. Rev. Lett. 49 , 1408–1412 (1982).

Joint Soviet-United States Statement on the Summit Meeting in Geneva. Ronald Reagan Presidential Library https://go.nature.com/36jiCCK (1985).

Letter from Hans Blix to IFRC members. IAEA Archives (IAEA, 1985).

Establishment of ITER: Relevant Documents . ITER Documentation Series No.1 (IAEA, 1988).

Letter from John F. Clarke to Hans Blix. IAEA Archives (IAEA, 1988).

Team, J. E. T. Nucl. Fusion 32 , 187–203 (1992).

Bell, M. G. et al. Overview of DT results from TFTR. Nuclear Fusion 35 , 1429–1436 (1995).

Ishida, S. et al. Phys. Rev. Lett. 79 , 3917–3921 (1997).

Keilhacker, M. et al. Nucl. Fusion 39 , 209–234 (1999).

Agreement on the Establishment of the ITER International Fusion Energy Organization for the Joint Implementation of the ITER Project INFCIRC/702 (IAEA, 2007); https://go.nature.com/3gbP5zu

Ayrault, J.-M. Decree no. 2012–1248. Journal Officiel de la République Française (2012); https://go.nature.com/2ZpeKyX

Klinger, T. et al. Nucl. Fusion 59 , 11204 (2019).

Download references

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Barbarino, M. A brief history of nuclear fusion. Nat. Phys. 16 , 890–893 (2020). https://doi.org/10.1038/s41567-020-0940-7

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Published : 11 June 2020

Issue Date : September 2020

DOI : https://doi.org/10.1038/s41567-020-0940-7

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