US scientists set to announce breakthrough in fusion energy

WASHINGTON (AP) — Energy Secretary Jennifer Granholm was set to announce on Tuesday a “major scientific breakthrough” in the decades-long quest to harness fusion, the energy that powers the sun and stars.

Researchers at Lawrence Livermore National Laboratory in California have for the first time produced more energy in a fusion reaction than used to ignite it, in what is called a net energy gain, according to a government official and a scientist familiar with research. Both spoke on condition of anonymity as they were not authorized to discuss the breakthrough before the announcement.

Granholm was scheduled to appear alongside Livermore researchers at a morning event in Washington. The Department of Energy declined to give details in advance. The news was first reported by the Financial Times.

Fusion proponents hope it could one day produce nearly limitless, carbon-free energy, replacing fossil fuels and other traditional energy sources. Generating the energy that powers homes and businesses from fusion is still decades away. But the researchers said it was an important step nonetheless.

“It’s almost like it’s a kickstarter,” said Professor Dennis Whyte, director of the Plasma Science and Fusion Center at the Massachusetts Institute of Technology and a leader in fusion research. “We should strive to make fusion energy systems available to combat climate change and energy security.”

Net energy gain has been an elusive goal because fusion occurs at such high temperatures and pressures that it is incredibly difficult to control.

Fusion works by pressing hydrogen atoms together with such force that they combine into helium, releasing huge amounts of energy and heat. Unlike other nuclear reactions, it does not create radioactive waste.

Billions of dollars and decades of work have gone into fusion research that has produced exhilarating results – for fractions of a second. Previously, researchers at the National Ignition Facility, the division of Lawrence Livermore where the success occurred, used 192 lasers and temperatures several times hotter than the center of the sun to create an extremely brief fusion reaction.

The lasers focus an enormous amount of heat on a small metal box. The result is a superheated plasma environment where fusion can occur.

Riccardo Betti, a professor at the University of Rochester and an expert in laser fusion, said an announcement that the net energy was gained during a fusion reaction would be significant. But he said there is a long way to go before the result generates sustainable electricity.

He likened the breakthrough to when humans first learned that refining oil into gasoline and igniting it could produce an explosion.

“You still don’t have the engine and you still don’t have the tires,” Betti said. “You can’t say you have a car.”

Realizing the net energy gain applied to the fusion reaction itself, not the total amount of energy needed to operate the lasers and complete the project. For fusion to be viable, it will need to produce much more power and for longer.

It is incredibly difficult to control star physics. Whyte said it was difficult to reach this point because the fuel has to be hotter than the center of the sun. Fuel doesn’t want to stay hot – it wants to leak and cool. Containing it is an incredible challenge, he said.

According to Jeremy Chittenden, a professor at Imperial College London who specializes in plasma physics, the net energy gain is not a huge surprise from the California lab given the progress it has already made.

“It doesn’t take away from the fact that this is an important step,” he said.

It takes tremendous resources and effort to advance fusion research. One approach turns hydrogen into plasma, an electrically charged gas, which is then controlled by huge magnets. This method is being explored in France as part of a collaboration between 35 countries called the International Thermonuclear Experimental Reactor as well as by researchers from the Massachusetts Institute of Technology and a private company.

Last year, teams working on these projects on two continents announced significant advances in the life-saving magnets needed for their work.


Mathew Daly reported from Washington. Maddie Burakoff reported from New York, Michael Phillis from St. Louis and Jennifer McDermott from Providence, RI


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