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 would be a milestone in a decades-long quest to unleash an infinite source of clean energy that could help end fossil fuel addiction. For decades, researchers have tried 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 an enormous amount of energy in the form of heat. Unlike nuclear fission, which supplies electricity to the whole world, it does not generate long-lived radioactive waste.
Scientists around the world have come closer to the breakthrough, using different methods to try to achieve the same goal.
The National Ignition Facility project creates energy from nuclear fusion through what is called “thermonuclear inertial fusion”. In practice, scientists in the US fire pellets containing hydrogen into an array of nearly 200 lasers, essentially creating a series of extremely rapid repeated explosions at the rate of 50 times per second.
The energy collected by neutrons and alpha particles is extracted as heat, and this heat holds the key to energy production.
“They contain the fusion reaction by bombarding the outside with lasers,” Tony Roulstone, a fusion expert with the University of Cambridge’s engineering department, told CNN. “They heat the outside; it creates a shock wave.
While getting a net energy gain from nuclear fusion is a big deal, it happens on a much smaller scale than what is needed to power power grids and heat buildings.
“This is 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 powerhouse, we need to make a bigger energy gain – we need it to be a lot more.”
In the UK, scientists are working with a huge doughnut-shaped machine fitted with giant magnets called tokamak to try to generate the same result.
After injecting a small amount of fuel into the tokamak, giant magnets are activated to create a plasma. The plasma must reach at least 150 million degrees Celsius, 10 times hotter than the core of the sun. This forces the fuel particles to coalesce into one. With nuclear fusion, the fused product has less mass than the original atoms. The missing mass converts into an enormous amount of energy.
The neutrons, capable of escaping from the plasma, then strike 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.
Last year, scientists working near Oxford were able to generate a record amount of sustained power. Even so, it only lasted 5 seconds.
Whether using magnets or firing pellets with lasers, the result is ultimately the same: the heat maintained by the process of fusing atoms holds the key to helping generate energy.
The big challenge in harnessing fusion power is sustaining it long enough to power power grids and heating systems around the world.
Chittenden and Roulstone told CNN that scientists around the world must now strive to dramatically scale up their fusion projects and also cut costs. For it to be commercially viable, it will take years of additional research.
“Right now, we’re spending an awful lot of time and money on every experiment we do,” Chittenden said. “We have to reduce the cost by a huge factor.”
However, Chittenden called this new chapter in nuclear fusion “a real watershed moment that is hugely exciting.”
Roulstone said there is still a long way to go before fusion can generate 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.”