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Cnn
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For the first time ever, US scientists at the National Ignition Facility of Lawrence Livermore National Laboratory in California have successfully produced a nuclear fusion reaction resulting in a net energy gain, a source close to 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 huge step in a decades-long quest to unleash an endless source of clean energy that could help end dependence on fossil fuels. Researchers have for decades attempted to recreate nuclear fusion, replicating the fusion that powers the sun.
US Energy Secretary Jennifer Granholm will make an announcement Tuesday about a “major scientific breakthrough,” the department announced Sunday. The breakthrough was first reported by the Financial Times.
Nuclear fusion occurs when two or more atoms are fused into a larger one, a process that generates a huge amount of energy in the form of heat. Unlike nuclear fission which powers electricity worldwide, it does not generate long-lived radioactive waste.
Scientists around the world have come close to breaking through, using different methods to try to achieve the same goal.
The National Ignition Facility project creates energy from nuclear fusion by what is known as “thermonuclear inertial fusion.” In practice, US scientists fire pellets containing a hydrogen fuel into an array of nearly 200 lasers, essentially creating a series of extremely fast, repeating explosions at a rate of 50 times per second.
The energy collected from the neutrons and alpha particles is extracted as heat, and that heat is the key to producing energy.
“They contain the fusion reaction by bombarding the outside with lasers,” Tony Roulstone, a fusion expert in the University of Cambridge’s Engineering Department, told CNN. “They warm up the outside; which creates a shock wave.
While getting a net energy gain from nuclear fusion is a big deal, it’s happening on a much smaller scale than it takes to power power grids and heat buildings.
“That’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. “To turn it into a power plant, we need to get more energy gain – we need it to be substantially more.”
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In the UK, scientists are working with a huge donut-shaped machine fitted with giant magnets called a tokamak to try and generate the same result. The missing mass converts into a huge amount of energy. The neutrons, which are able to escape the plasma, then strike 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, create steam, and power turbines to generate power.
The machine that generates the reaction must undergo strong heat. The plasma must reach at least 150 million degrees Celsius, 10 times hotter than the sun’s core.
Scientists working near Oxford were able to generate a record amount of sustained energy last year. Even so, it only lasted 5 seconds.
Whether using magnets or firing pellets with lasers, the result is ultimately the same: The heat sustained by the fusing process of atoms is key to helping produce energy.
The big challenge of harnessing fusion energy is to sustain it long enough to power electricity grids and heating systems around the world.
Chittenden and Roulstone told CNN that scientists around the world now have 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’re spending an enormous amount of time and money on every experiment we do,” Chittenden said. “We have to reduce costs by a huge factor.”
However, Chittenden called this new chapter in nuclear fusion “a real watershed moment that is tremendously exciting.”
Roulstone said there are many shows that still have work to do to make fusion capable of generating electricity on a commercial scale.
“The opposing argument is that this result is miles away from the actual energy gain required for electricity generation,” he said. “Therefore, we can say that it is a success of science, but far from providing any useful energy.”
