fusion experiment success

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.

US scientists repeat fusion ignition breakthrough for 2nd time

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Reporting by Lavanya Ahire in Bengaluru and Doina Chiacu in Washington; additional reporting by Yana Gaur; Editing by Leslie Adler and Diane Craft

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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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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.

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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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The U.S. Nuclear Fusion Breakthrough Is a Huge Milestone—But Unlimited Clean Energy Is Still Decades Off

I n some ways, scientists at the Department of Energy’s National Ignition Facility (NIF) have been a bit down and out. The $3.5 billion facility was designed to replicate the atom-smashing reactions that occur inside the sun, a difficult process that requires enormous amounts of heat and pressure, and could theoretically solve humanity’s energy and climate woes.

But technical obstacles put NIF a decade behind in its goal of achieving fusion “ignition,” that is, getting more energy out of one of those reactions than it put in. The facility uses the largest lasers in the world to try and do that, focusing energy on a tiny capsule filled with hydrogen isotopes. But those lasers, based on 1980s technology, were in some ways already dated by the time they were installed, taking hours to cool down each time they are fired. And much of the team’s resources aren’t even devoted to achieving the holy grail of nuclear fusion, instead being focused on weapons research .

On Dec. 5—after decades of effort —scientists at the laboratory finally created a controlled fusion reaction that released more energy than the researchers blasted into it, an important step toward the long sought-after goal of generating almost unlimited power from clean, plentiful fusion energy. (Notably we have uncontrolled fusion reactions down pat—they’re the basis of hydrogen bombs). After bringing in an external team of scientists to confirm the findings, the U.S. Department of Energy (DOE) announced the development on Dec. 13. “This is a landmark achievement for the researchers and staff at the National Ignition Facility,” said Energy Secretary Jennifer Granholm in a press release. “This milestone will undoubtedly spark even more discovery.”

“We were not sure if it was ever going to work,” says Peter Littlewood, a physics professor at the University of Chicago and former director of Argonne National Lab, a DOE research center. “They deserve a tremendous amount of credit for slogging through this.”

Today’s news builds on a notable success achieved by the National Ignition Facility in August 2021, when it fired its lasers on a capsule of deuterium and tritium (hydrogen atoms with an extra one or two neutrons, respectively), setting off a reaction that unleashed 1.3 megajoules (MJ) of energy. It wasn’t as much as the 1.9 MJ that the lasers blasted into it, but it was still eight times more energy output than the facility’s previous record. Then, for months afterward, the NIF team failed to replicate the results. Whisperings started, with some physics community observers calling for the facility to finally be shut down. In July of this year, Nature reported that scientists at NIF had ceased trying to replicate their results from last year, and were instead focusing on a new strategy. It seems that focus has now paid off.

The NIF success also comes a few months after another successful fusion experiment in the U.K. Instead of lasers, scientists there used a donut-shaped tokamak, a machine that uses magnetic fields to heat hydrogen atoms to extraordinary temperatures in order to create a fusion reaction. Though that experiment didn’t reach the break-even point in terms of energy output, the results helped validate an approach being pursued by a multi-nation consortium building the larger $22 billion ITER (International Thermonuclear Experimental Reactor) tokamak project in France. That project, its designers claim, will create a reaction that outputs ten times more energy than researchers add in.

Scientists have been trying for decades to generate an output like the one achieved at the NIF, and the results are undoubtedly an important scientific and technical milestone. But tokamak technology is closer to potential commercialization than the NIF laser approach; Energy Department officials say that pursuing both methods is important to building up the science of nuclear fusion.

Fusion technology still faces an array of extremely difficult technical hurdles, and Littlewood says it will be decades before it could potentially be used to power homes and businesses, if it ever reaches that point at all. He terms the technology a “hail mary pass” to solve the climate crisis (fusion reactions produce no emissions, and wouldn’t have the meltdown risk or difficulties disposing of used fuel that plague nuclear fission reactors .) But the new experimental results don’t exactly mean that the technology will be coming any sooner, he says. “This isn’t really dancing in the streets. It’s more, ‘Phew, finally we got here.’”

It’s important also to keep in mind the amount of energy that researchers managed to generate. The result of the recent DOE experiment might be characterized as a small explosion, but the 3.15 MJ it outputted is equivalent to the energy content of about a tenth of a gallon of gasoline. Notably, the energy that the lasers input into the reaction, 2.05 MJ, is only a tiny share of the 300 MJ of energy the facility needed to run the experiment. “I don’t want to give you the sense that we’ll plug the NIF into the grid,” said Kim Budil, director of Lawrence Livermore National Laboratory, speaking in a press conference on Dec. 13. “That is definitely not how this works.”

The private sector has poured close to $5 billion dollars into commercializing fusion energy, with many companies trying out creative alternate approaches that are different from those being pursued by public research groups at NIF and ITER. Michl Binderbauer, CEO of commercial fusion company TAE Technologies, is much more optimistic about the timeline to potential commercialization than Littlewood—he says commercial fusion power plants could be coming in the next ten years.

“I think for humanity [the NIF experiment] should induce an enormous amount of confidence that we’re going to get there,” Binderbauer says. “It’s an enormous point of validation that we weren’t just chasing ghosts.”

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Fusion Breakthrough: US Experiment Hits Monumental 'Ignition' Milestone

Scientists have made a "breakthrough" in their quest to harness nuclear fusion .

The US Department of Energy officially announced the milestone in fusion energy research on Tuesday.

For the first time, researchers created a nuclear fusion reaction that produced more energy than they put into it.

The experiment, conducted on December 5 at Lawrence Livermore National Laboratory in California, generated 3.15 megajoules of energy, more than the 2.05 megajoules put into creating it.

"Scientifically, this is the first time that they showed that this is possible," Gianluca Sarri, a physicist at Queen's University Belfast, told New Scientist . "From theory, they knew that it should happen, but it was never seen in real life experimentally."

What is fusion energy and why is it a big deal?

Nuclear fusion works by forcing together two atoms – most often hydrogen – to make a heavier one – like helium.

This explosive process releases massive amounts of energy, the Department of Energy explains. Fusion is the opposite of fission , the reaction that powers nuclear reactors used commercially today.

Fusion occurs naturally in the heart of the Sun and the stars, providing these cosmic objects with fuel.

Since the 1950s , scientists have been trying to replicate it on Earth in order to tap into what nuclear energy advocates suggest is clean, cheap, and almost limitless electricity.

According to the International Atomic Energy Agency, fusion generates four times more energy per kilogram than the fission used to power nuclear plants, and nearly 4 million times more energy than burning oil or coal.

What's more, unlike fossil fuels, fusion doesn't release carbon dioxide – the greenhouse gas that's the main driver of climate change – into the atmosphere. And unlike nuclear fission, fusion doesn't create long-lived radioactive waste, according to the Department of Energy .

But so far, nuclear fusion hasn't solved our energy problems on a grand scale.

What Tuesday's 'breakthrough' announcement means for the future

Tuesday's announcement is a huge step forward in nuclear fusion energy, but applying the technology at commercial scale is likely still years away.

Chanda Prescod-Weinstein, a theoretical physicist, pointed out that the process the Department of Energy uses requires tritium , a rare and radioactive isotope of hydrogen.

"It may yet yield important information that is ultimately transformative. We don't know yet," Prescod-Weinstein tweeted on Monday . "Being able to do this once a day with a laser does not at all mean that this mechanism will scale!"

Investors, including Amazon founder Jeff Bezos , have poured billions into clean energy startups trying to make fusion commercially viable, and Tuesday's announcement is likely to continue that trend.

This article was originally published by Business Insider .

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• NEWS FEATURE
• 13 December 2023

Nuclear-fusion breakthrough: this physicist helped to achieve the first-ever energy gain

• Jeff Tollefson

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Credit: Cayce Clifford for Nature

This story is part of Nature’s 10 , an annual list compiled by Nature’s editors exploring key developments in science and the individuals who contributed to them.

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Nature 624 , 500-501 (2023)

doi: https://doi.org/10.1038/d41586-023-03923-5

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