It’s a technology that has the potential to one day accelerate the planet’s shift away from fossil fuels, which are major contributors to climate change. Technology has long struggled with daunting challenges.
Here’s exactly what nuclear fusion is, and some of the difficulties in making it the cheap, carbon-free energy source scientists believe it can be.
Look up and it’s happening right above you: Nuclear fusion reactions power the sun and other stars.
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The reaction occurs when two light nuclei fuse to form a single heavier nucleus. Because the total mass of that single nucleus is less than the mass of the two original nuclei, the leftover mass is energy released in the process, according to the Department of Energy.
In the case of the sun, its intense heat (millions of degrees Celsius) and the pressure exerted by its gravity allow atoms to fuse that would otherwise repel each other.
Scientists have long known how nuclear fusion has worked and have been trying to duplicate the process on Earth since the 1930s. Current efforts are focused on fusing a pair of isotopes hydrogen, deuterium and tritium, according to the Department of Energy, which says that particular combination releases “much more energy than most fusion reactions” and requires less heat to do so.
HOW VALUABLE WOULD THIS BE?
Daniel Kammen, a professor of energy and society at the University of California at Berkeley, said nuclear fusion offers the possibility of “basically unlimited” fuel if the technology can be made commercially viable. The necessary items are available in seawater.
It’s also a process that doesn’t produce the radioactive waste from nuclear fission, Kammen said.
HOW ARE SCIENTISTS TRYING TO DO THIS?
One way that scientists have tried to recreate nuclear fusion involves what’s called a tokamak, a doughnut-shaped vacuum chamber that uses powerful magnets to turn fuel into a superheated plasma (between 150 million and 300 million degrees Celsius). ) where fusion can occur.
The Livermore lab uses a different technique: Researchers fire a 192-beam laser at a small capsule filled with deuterium and tritium fuel. The lab reported that an August 2021 test produced 1.35 megajoules of fusion energy, roughly 70% of the energy fired at the target. The lab said that several subsequent experiments showed diminishing results, but the researchers believed they had identified ways to improve the quality of the fuel capsule and the symmetry of the lasers.
“The most critical feature of moving fusion from theory to commercial reality is taking more energy out than going in,” Kammen said.
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