Sustainability Energy

What is nuclear fusion?

“Tomorrow’s announcement is not the first major breakthrough in fusion research, nor will it be the last. But, it demonstrates continued progress and makes clear how scientists are successfully developing the know-how to bring the energy of the stars to Earth.”
An image of stars.
Nuclear fusion is the same energy that powers the sun and stars. iStock.

Story at a glance


  • Energy Secretary Jennifer Granholm is expected to announce a major scientific breakthrough on Tuesday, according to numerous media reports.

  • It’s anticipated Granholm will announce federal scientists successfully achieved a net energy gain in a nuclear fusion reaction for the first time. 

  • If true, the breakthrough will mark a significant step forward in the quest for a zero-carbon energy source. 

Government scientists are expected to make a major announcement Tuesday regarding a breakthrough in nuclear fusion technology, according to a report from the Financial Times

Preliminary results of an experiment are anticipated to show that scientists have achieved a net energy gain in a fusion reaction for the first time, marking a step forward in pursuit of near limitless, zero-carbon power that doesn’t produce large amounts of radioactive waste. 

But what exactly is this technology and why do some hail it as a “holy grail” for clean energy?

Nuclear fusion is the same energy that powers the sun and stars, and is created when nuclei from two light atoms combine at high speeds. These atoms go on to create the nucleus of a heavier atom and generate energy in the process. 

That energy can be used to power homes and offices without emitting carbon into the air, dumping radioactive waste into the environment, and absent the threat of a nuclear meltdown.  

In contrast, current nuclear power plants create energy by splitting uranium atoms (i.e. nuclear fission) and produce long-lived toxic nuclear waste

Nuclear fusion also uses fewer resources than other clean energy options like solar or wind power. Its main fuel consists of two hydrogen isotopes: deuterium, which can be found in water, and tritium, which can be produced from lithium. The energy created from one gram of deuterium-tritium is equal to the energy from approximately 2,400 gallons of oil

Overall, “the fuel is abundant,” said Eugenio Schuster, a professor in the department of mechanical engineering and mechanics at Lehigh University, in an interview with Changing America.

“When we compare with nuclear fission, it has some advantages too, in the sense that there is no risk of nuclear accidents as we know them,” Schuster added. “Although the probability of these accidents to happen in present nuclear-fission power plants with the technology we have is almost zero”. 


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Nuclear fusion has been touted as one way to bring cheap electricity to impoverished regions, as, according to the Financial Times, just a small cup of the hydrogen fuel produced could theoretically power a house for hundreds of years. 

But to achieve fusion, it is crucial that reactors create more energy than they take in. 

The announcement from the National Ignition Facility (NIF) at the federal Lawrence Livermore National Laboratory in California, is expected to say researchers have done just that. The process is dubbed inertial confinement fusion and uses one of the largest lasers in the world to produce what is essentially a man-made star. 

The Financial Times reports the fusion at the California facility produced around 2.5 megajoules of energy, marking about 120 percent of the 2.1 megajoules of energy in the lasers, although the data are still being analyzed. 

“The achievement at NIF represents the very best in modern science,” Michael Mauel, a professor of applied physics at Columbia University, told Changing America. 

“It comes from more than a hundred dedicated scientists who have worked for more than a decade to produce net fusion energy safely in the laboratory,” Mauel said. Mauel did not have early access to the details of tomorrow’s announcement, but based his comments on reports of the breakthrough. 

Scientists have been investigating nuclear fusion since the 1950s, and despite the anticipated breakthrough, the technology is still years away from commercial implementation. 

Fusion reactions take place in plasma that can reach 100 million to 200 million degrees Celsius, and can be contained by either magnetic fields or compressing the fuel with lasers. To implement the fusion on a broad scale, materials and structures need to be designed that can withstand these conditions over time. 

But it remains unknown whether the technology can be implemented on a wide enough scale in time to meaningfully alter the course of climate change. The U.S. power grid would also need to undergo a redesign before fusion plants become commonplace.

“Fusion is a big promise in terms of generation of energy and it will play a critical role in our portfolio of green sources of energy,” Schuster said. 

Over the years, billions of dollars from governments and private corporations have funded research on the technology.

A collaboration between China, the European Union, India, Japan, Russia, South Korea and the United States led to the creation of the International Thermonuclear Experimental Reactor (ITER) in Southern France, which uses a Russian-inspired reactor called a tokamak.

In contrast to the NIF, ITER uses a magnetic field to hold the plasma in place, so researchers can extract heat without setting the walls of the reactor on fire. 

“Tomorrow’s announcement is not the first major breakthrough in fusion research, nor will it be the last,” Mauel said. “But, it demonstrates continued progress and makes clear how scientists are successfully developing the know-how to bring the energy of the stars to Earth.” 

Energy Secretary Jennifer Granholm is expected to make the announcement. 


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