MIT researchers have found a way to get rid of excess heat that cause structural damage to fusion power plants.
The new solution is composed of high-temperature superconducting magnets.
The new design, unlike that of typical fusion plants, makes it possible to open the device’s internal chamber and replace critical components.
According to the researchers, this capability is essential for MIT’s newly proposed heat-draining mechanism.
Inthe words of Professor Dennis Whyte, director of MIT’s Plasma Science and Fusion Center, the shedding of heat from inside a fusion plant can be compared to the exhaust system in a car.
In the new design, the ‘exhaust pipe’ is much longer and wider than is possible in any of today’s fusion designs, making it much more effective at shedding the unwanted heat.
Fusion harnesses the reaction that powers the sun itself, holding the promise of eventually producing clean, abundant electricity using a fuel derived from seawater – deuterium, a heavy form of hydrogen, and lithium – so the fuel supply is essentially limitless.
Unfortunately, decades of research toward such power-producing plants have still not led to a device that produces as much power as it consumes, much less one that actually produces a net energy output.
Most of the energy produced inside a fusion reactor is emitted in the form of neutrons, which heat a material surrounding the fusing plasma, called a blanket.
In a power-producing plant, that heated blanket would in turn be used to drive a generating turbine.
But about 20 percent of the energy is produced in the form of heat in the plasma itself, which somehow must be dissipated to prevent it from melting the materials that form the chamber.
No material is strong enough to withstand the heat of the plasma inside a fusion device. That is why the plasma is held in place by powerful magnets that prevent it from ever coming into direct contact with the interior walls of the donut-shaped fusion chamber.
In typical fusion designs, a separate set of magnets is used to create a sort of side chamber to drain off excess heat, but these so-called divertors are insufficient for the high heat in the new, compact plant.
The new MIT-originated design known as ARC (Advanced, Robust, and Compact) features magnets built in sections so they can be removed for service.
According to the researchers, this makes it possible to access the entire interior and place the secondary magnets inside the main coils instead of outside, thereby ensuring more efficient reactors.
ARC rendering by Alexander Creely/MIT