For the first time ever, US scientists have successfully performed a nuclear fusion reaction that resulted in a net energy gain at Lawrence Livermore National Laboratory’s National Ignition Facility in California, a source familiar with the project confirmed to CNN.
The US Department of Energy is expected to officially announce the breakthrough on Tuesday.
The result of the experiment would be a giant step in a decades-long quest to unlock an infinite source of clean energy that could help end dependence on fossil fuels. For decades, researchers have tried to replicate nuclear fusion – a replica of the fusion that powers the sun.
US Energy Secretary Jennifer Granholm will make an announcement on Tuesday about a “major scientific breakthrough,” the department said on Sunday. The breakthrough was first reported by the Financial Times.
Nuclear fusion occurs when two or more atoms fuse into one larger one, a process that produces a tremendous amount of energy in the form of heat. Unlike nuclear fission, which generates electricity anywhere in the world, it does not produce long-lived radioactive waste.
Scientists around the world are approaching the breakthrough by using different methods to achieve the same goal.
The National Ignition Facility project produces nuclear fusion power through what is known as “inertial thermonuclear fusion”. In practice, US scientists fire pellets containing a hydrogen fuel into a series of nearly 200 lasers, essentially creating a series of extremely rapid, repeated explosions at a rate of 50 times per second.
The energy collected by the neutrons and alpha particles is extracted as heat, and this heat is key to energy production.
“They contain the fusion reaction by bombarding the outside with lasers,” Tony Roulstone, a fusion expert from the University of Cambridge’s Department of Engineering, told CNN. “They heat up the outside; that creates a shock wave.”
While achieving net energy gain from nuclear fusion is a big deal, it is happening on a much smaller scale than is needed to power grids and heat buildings.
“It’s about what it takes to boil 10 kettles of water,” said Jeremy Chittenden, co-director of the Center for Inertial Fusion Studies at Imperial College London. “In order to turn this into a power plant, we have to generate more energy – we need significantly more.”
In the UK, scientists are working with a giant donut-shaped machine equipped with giant magnets called a tokamak to try and achieve the same result.
After a small amount of fuel is injected into the tokamak, giant magnets are activated to create a plasma. The plasma must reach at least 150 million degrees Celsius, ten times hotter than the core of the sun. This forces the particles from the fuel to fuse into one. In nuclear fusion, the fusion product has less mass than the original atoms. The missing mass converts into an enormous amount of energy.
Neutrons that manage to escape the plasma then hit a “blanket” lining the walls of the tokamak, and their kinetic energy is transferred as heat. This heat can then be used to heat water, produce steam, and drive turbines to generate electricity.
Last year scientists working near Oxford were able to generate a record-breaking amount of sustainable energy. Still, it only lasted 5 seconds.
Whether magnets are used or pellets are fired with lasers, the end result is the same: the heat generated by the process of atom fusion is key to power generation.
The major challenge in harnessing fusion energy is sustaining it long enough for it to power grids and heating systems around the world.
Chittenden and Roulstone told CNN that scientists around the world now need to work to dramatically scale up their fusion projects and also cut costs. Making it commercially viable will require years of further research.
“Right now, we invest a tremendous amount of time and money into every experiment we do,” Chittenden said. “We need to reduce costs by a huge factor.”
However, Chittenden called this new chapter in nuclear fusion “a true breakthrough moment that is tremendously exciting”.
Roulstone said there is still work to be done to make fusion capable of generating electricity on a commercial scale.
“The counter-argument is that this result is miles away from the actual energy gain needed to generate electricity,” he said. “Therefore we can say that (it) is a success of science, but far from providing useful energy.”