US scientists achieve long-awaited breakthrough in nuclear fusion, source says

CNN
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For the first time ever, US scientists at the National Ignition Facility at 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 is a milestone in a decades-long quest to unleash an infinite source of clean energy that could help end dependence on fossil fuels. Researchers have tried for decades to recreate nuclear fusion – replicating the fusion that powers the sun.

US Energy Secretary Jennifer Granholm will make an announcement on Tuesday about a “major scientific breakthrough”, the department announced on Sunday. The breakthrough was first reported by the Financial Times.

Nuclear fusion occurs when two or more atoms are fused into a single larger one, a process that generates a massive amount of energy in the form of heat.

Scientists around the world have approached the breakthrough; in February, British scientists announced that they had more than doubled the previous record for generating and maintaining nuclear fusion.

In a huge doughnut-shaped machine called a tokamak fitted with giant magnets, scientists working near Oxford were able to generate a record amount of sustained energy. Even so, it only lasted 5 seconds.

The heat sustained by the process of fusing atoms holds the key to helping generate energy.

As CNN reported earlier this year, the fusion process creates helium and neutrons — which are lighter than the parts they were originally made from.

The missing mass then converts into an enormous amount of energy. The neutrons, capable of escaping from the plasma, then hit a “blanket” lining the walls of the tokamak, and their kinetic energy is transferred in the form of heat. This heat can then be used to heat water, create steam and power turbines to generate electricity.

The machine that generates the reaction must be very hot. The plasma must reach at least 150 million degrees Celsius, 10 times hotter than the core of the sun.

The big challenge in harnessing fusion power is sustaining it long enough to power power grids and heating systems around the world.

A British fusion scientist told CNN the result of the US breakthrough is promising, but also shows there is still work to be done to make fusion capable of generating electricity on a commercial scale.

“They worked on the design and the composition of the target and the shape of the energy pulse to get much better results,” Tony Roulstone, from the University of Cambridge’s engineering department, told CNN.

“The counter argument is that this result is miles away from the actual energy gain needed to generate electricity. Therefore, we can say that (it is) a success of science but far from providing useful energy.