Commonwealth Fusion Systems

Commonwealth Fusion Systems is a technology company developing fusion power systems based on ARC tokamak reactors that is headquartered in Cambridge, Massachusetts and was founded in 2017 by Martin Greenwald and Bob Mumgaard. Commonwealth Fusion Systems was spun out of the Massachusetts Institute of Technology and their Plasma Science and Fusion Center in 2007. They continue to collaborate with MIT's Plasma Science and Fusion Center to use their research into fusion technology.

Commonwealth Fusion Systems is working on designing and building commercial fusion energy machines through magnet technology. Their design includes a high-power superconducting magnet used to create conditions necessary for sustained fusion reaction. The reactor uses hydrogen isotopes kept under extreme pressure using the superconducting magnets to sustain the reaction and contain the resulting energy. For the reaction to occur, the hydrogen fuel source needs to be heated to tens of millions of degrees.

In September 2020, Commonwealth Fusion Systems published seven peer-reviewed papers validating their approach to commercial fusion energy. Part of these papers included the design of their SPARC system, which works to provide a net energy fusion system. The SPARC reactor is a tokamak reactor, similar to an ITER tokamak reactor which should enable a similar performance as an ITER tokamak reactor but at ten times smaller and on a faster timeline. The SPARC reactor is intended to move towards a viable commercial fusion power plant called ARC.

In part of their development of SPARC, Commonwealth Fusion Systems and MIT's Plasma Science and Fusion Center have collaborated on the manufacturing of a successful 20 Tesla, large-bore magnet by 2021.

Part of the construction of the fusion reactor involves the design and manufacture of Commonwealth Fusion Systems VIPER cable. This was a joint project between Commonwealth Fusion Systems and MIT's Plasma Science and Fusion Center. And the VIPER cable is a high-temperature superconductor cable that can be engineered into magnets directly. The cable can carry currents exceeding 50kA at magnetic fields exceeding 10 T. Further, the cable was tested under extreme electromagnetically induced mechanical forces to ensure there would be minimal performance degradation and ensure the cable would be resilient against the "quench" fault condition; the "quench" condition would cause the cable to lose its superconducting properties.