The nuclear fusion breakthrough in California is seen as a major milestone toward a clean energy future

The US Department of Energy announced Tuesday that US scientists have created “net energy” for the first time through a nuclear fusion reaction.

The successful experiment, conducted Dec. 5 at Lawrence Livermore National Laboratory, is the most significant milestone in the decades-old quest to produce cheap, clean, carbon-neutral energy through nuclear fusion.

“We have taken the first tentative steps toward a clean energy source that has the potential to revolutionize the world,” said Jill Hroby, director of the National Nuclear Security Administration.

Energy Secretary Jennifer M. Granholm called the achievement “one of the most impressive scientific achievements of the 21st century,” adding that it “will go down in the history books.”

In a nuclear fusion reaction, two atoms collide with each other and fuse into a larger atom of a heavier element, releasing their excess mass in the form of energy.

Fusion is the process by which the sun produces energy. The core of the Sun is an ideal high-pressure, high-temperature environment for hydrogen atoms to fuse into helium; Replicating these conditions on Earth has proven more difficult.

Scientists at Lawrence Livermore in the San Francisco Bay Area achieved their feat by training 192 lasers at a diamond-covered target roughly the size of a peppercorn, heating it to more than 3 million degrees Celsius (more than 5.4 million degrees Fahrenheit) and — briefly — mimicking the conditions of a star. Fusion has begun.

This has all happened before. “A hundred times before,” said Marvin Adams, NSA deputy director for defense programs. “But last week, for the first time, they designed this experiment so that fusion fuel stays hot enough, dense enough and round enough for long enough to ignite and produce more energy than the laser deposits.”

Those net energy gains were “about two megajoules, about three megajoules out,” Adams said.

The fusion reaction generates three to four times more energy than fission, which itself is almost a million times more powerful than any other energy source on Earth.

Nuclear fission, or the splitting of atoms, also releases a huge amount of energy in a chain reaction. Fission reactions have been productively directed at nuclear power plants and destructively directed at nuclear weapons.

Unlike nuclear fission, nuclear fusion does not release harmful radioactive byproducts that take thousands of years to decay. And since it does not involve a chain reaction, it is intrinsically less dangerous.

In addition, merging has long been seen as key to achieving the goal of net zero emissions. Electricity and heat production currently account for 30% of global greenhouse gas emissions. Technology that successfully harnesses nuclear fusion could, in theory, create endless renewable amounts of clean, low-risk, zero-carbon energy.

All of these factors have made controlled nuclear fusion one of science’s most desirable goals since the 1950s, attracting billions in government and private investment.

said Lee Bernstein, a professor of nuclear engineering at the University of California, Berkeley and former group vice president at the National Ignition Facility at the Livermore Laboratory, where the experiment took place.

While Tuesday’s announcement is a huge step toward that ideal, there is a long way to go. Any practical application will likely be “contracts,” said Kim Podell, director of Livermore.

“This is one igniting capsule, at once. To achieve commercial fusion energy, you have to do many things. You have to be able to produce many fusion ignition events per minute.” “With a combination of effort and investment, a few decades of research on the underlying technologies can put us in a position to build a power plant.”

Indeed, the achievement in Livermore is “a bit like the first flight of the Wright brothers,” said Paul Bellan, a plasma physicist at Caltech.

With their own designed plane, Orville and Wilbur Wright proved in 1903 that “you can make a heavier-than-air plane that takes off and flies and doesn’t fall,” Bellan said. “Not that you can fly from Los Angeles to London” right away. He added that did not mean that the Wrights’ plane was the only possible aircraft design. But it proved that a bold leap into physics was possible and inspired others to build on their success.

“It’s definitely a defining moment,” Bilan said. “It shows that it’s worth working on and eventually, we’ll come up with something that will be profitable.”

While fusion can take decades to reach commercial readiness, nuclear fission technology has powered the United States for decades. Ninety-three nuclear reactors produced nearly a fifth of the country’s electricity last year. Among them is the Palo Verde plant off Interstate 10 in Arizona, which supplies Los Angeles and other cities and is the largest generator of electricity in the country. President Biden sees nuclear power as essential to achieving his goal of 100% green electricity by 2035.

Even before Tuesday’s historic announcement, a string of successes at the National Ignition Facility had inspired new generations of science talent. Since August 2021, when the team reached a key threshold in achieving a self-sustaining reaction, student interest in the fusion has increased, said Siegfried Glenzer, professor of photon science at Stanford University and division director at the SLAC National Accelerator Laboratory.

“This is really a big draw right now for young people who want to make a difference in the world. Many are driven by climate change, and they want to see the production of a carbon-neutral energy source,” Glenzer said. “It’s an exciting time for researchers of any age.”

Times staff writer Sammy Roth contributed to this report.