The tokamak fusion reactor design uses a magnetic field to contain hot fusion fuel in the form of plasma within a donut-shaped vessel. While not in itself a new approach, the researchers say that advances in magnet technology have enabled them to develop a practical tokamak reactor design - called ARC - that is both smaller and less-expensive than much larger reactors.
Key to the design are new commercially available second-generation superconductors that make it possible to produce a stronger magnetic field to contain the super-hot plasma in a much smaller volume than those previously proposed. In this case the enabling technology is rare-earth barium copper oxide (REBCO) superconducting tapes, which would be used to create the reactor's high-magnetic-field coils.
According to the researchers, the new superconductors can increase fusion power by "about a factor of 10" compared to a reactor using standard superconducting technology, such as the large ITER Tokamak fusion project currently underway in France. The MIT team estimates that their ARC design would be about half the diameter of ITER while producing the same amount of power, and be less expensive and quicker to build.
Currently the new proposed design is estimated to be capable of producing about three times as much electricity as is needed to keep it running, but that amount could likely be optimized further to as much as five or six times. According to the researchers, this net energy production presents a major breakthrough in fusion reactor research, as up to now no fusion reactor has produced as much energy as it consumes.
The proposed design could produce a reactor that could provide electricity to about 100,000 people, say the researchers, and reactors of similar complexity and size have been built within about five years. For more, see their paper in the journal Fusion Engineering and Design : " ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable