A viable nuclear fusion reactor – one that spits out more energy than it consumes – could be here as early as 2025.
This is the result of seven new studies, published on September 29 on Journal of Plasma Physics.
If a fusion reactor reaches this milestone, it could pave the way for massive clean energy generation.
During merger, the atomic nuclei are forced together to form heavier atoms. When the mass of the resulting atoms is less than the mass of the atoms that went into their creation, the excess mass is converted into energy, releasing an extraordinary amount of light and heat. Fusion feeds the sun and the stars, like the powerful severity to their hearts they melt hydrogen create helium.
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But an enormous amount of energy is needed to force atoms to fuse together, which occurs at temperatures of at least 180 million degrees Fahrenheit (100 million degrees Celsius). However, such reactions can generate much more energy than they require. At the same time, the merger does not produce greenhouse gases like carbon dioxide, which drives global warming, nor does it generate other pollutants. And the fuel for fusion, like the element hydrogen – is quite abundant on Land to meet all of humanity’s energy needs for millions of years.
“Virtually all of us have gotten into this research because we’re trying to solve a really serious global problem,” said study author Martin Greenwald, a plasma physicist at MIT and one of the leading scientists developing the new reactor. “We want to impact society. We need a solution to global warming, otherwise civilization is in trouble. It looks like it could help solve it.”
Most experimental fusion reactors use a Russian donut-shaped design called tokamak. These designs use powerful magnetic fields confining a cloud of plasma, or ionized gas, to extreme temperatures, high enough for atoms to fuse together. The new experimental device, called the Soonest / Smallest Private-Funded Affordable Robust Compact (SPARC) reactor, was developed by scientists from MIT and a spinoff company, Commonwealth Fusion Systems.
If successful, SPARC would be the first device to achieve a “burning plasma”, in which the heat from all fusion reactions maintains the fusion without the need to pump extra energy. But no one has ever been able to harness the power of plasma combustion in a controlled reaction here on Earth, and more research is needed before SPARC can. The SPARC project, which started in 2018, is expected to begin construction next June, with the reactor starting operations in 2025. This is much faster than the world’s largest fusion energy project, known as the International Thermonuclear Experimental Reactor (ITER ), which was conceived in 1985 but only launched in 2007; and although construction began in 2013, the project is not expected to generate a melt reaction until 2035.
One advantage SPARC can have over ITER is that SPARC’s magnets are designed to confine its plasma. SPARC will use so-called high-temperature superconducting magnets that have only become commercially available in the past three to five years, long after ITER was designed. These new magnets can produce much stronger magnetic fields than ITER’s – a maximum of 21 tesla, compared to ITER’s maximum of 12. (In comparison, the Earth’s magnetic field varies in intensity from 30 millionths to 60 millionths of a tesla.)
These strong magnets suggest that the SPARC core may be about three times smaller in diameter and 60 to 70 times smaller in volume than the ITER heart, which should be 6 meters wide. “That drastic reduction in size is accompanied by a reduction in weight and cost,” Greenwald told Live Science. “This is really the turning point.”
In seven new studies, the researchers outlined the supercomputer calculations and simulations behind the SPARC project. According to studies, SPARC is expected to generate at least double 10 times more energy than pumped.
The heat of a fusion reactor would generate steam. This steam would then drive a turbine and an electric generator, in the same way that most electricity is produced today.
“Fusion power plants could replace fossil fuel power plants one by one, and you shouldn’t have to refurbish power grids for them,” Greenwald said. Conversely, renewable energy sources such as solar and wind “are not well received by the current design of electricity grids”.
Finally, the researchers hope that the SPARC-inspired fusion plants will generate between 250 and 1,000 megawatts of electricity. “In the current US electricity market, power plants typically generate between 100 and 500 megawatts,” Greenwald said.
SPARC would only produce heat, not electricity. Once the researchers have built and tested SPARC, they plan to build the Affordable Robust Compact (ARC) reactor, which would generate electricity from that heat by 2035.
“This is very ambitious, but this is the goal we are working towards,” Greenwald said. “I think it’s really plausible.”
Originally published in Live Science.