Commonwealth Fusion Systems (CFS) has made significant progress toward commercial fusion energy, successfully installing a critical component in its Sparc demonstration reactor.
Highlights
The newly placed 75-ton, 24-foot-wide stainless steel cryostat base serves as the foundation of the tokamak, a core component designed to generate more power than it consumes.
Cryostat Base
Manufactured in Italy and transported to CFS’s Devens, Massachusetts facility, the cryostat base plays an essential role in maintaining the extreme conditions required for fusion.
Acting as an insulating layer, it helps sustain the ultra-low temperatures necessary for superconducting magnets, which confine and compress plasma at temperatures exceeding 100 million degrees Celsius.
These magnets must be cooled to –253 degrees Celsius using liquid helium, and the cryostat base functions similarly to the bottom of a thermos, ensuring efficient temperature control.
CFS, supported by Breakthrough Energy Ventures, co-founded by Bill Gates, views this installation as a major turning point. “It is the first piece of the actual fusion machine,” said Alex Creely, CFS’s Director of Tokamak Operations.
The company has spent over three years constructing supporting infrastructure, and this marks the transition to assembling the reactor itself.
Fusion Energy’s Potential and Technological Approach
Fusion energy is often seen as a potential breakthrough for generating clean electricity, utilizing fuel sourced from seawater. With rising global energy demand—driven by the expansion of electric vehicles and data centers—fusion has garnered increasing attention as a long-term solution.
Unlike the Department of Energy’s National Ignition Facility (NIF), which uses lasers to initiate fusion, CFS’s tokamak design relies on superconducting magnets.
This approach aims to achieve net energy gain, meaning the reactor would produce more energy than it consumes. Sparc is expected to become operational in 2027, and if successful, it could pave the way for commercial-scale reactors.
In December 2024, CFS announced plans to build a commercial fusion power plant, known as ARC, in Chesterfield County, Virginia.
This facility, developed in collaboration with Dominion Energy Virginia, aims to generate 400 megawatts of clean electricity, sufficient to power approximately 150,000 homes.
The project is expected to drive significant economic development, creating hundreds of jobs during construction and operation.
Advancements in Superconducting Technology
CFS has been actively developing cutting-edge superconducting technologies to improve fusion reactor efficiency. In October 2024, the company introduced its PIT VIPER superconducting cable, designed to handle the high-energy pulses required in fusion systems.
This builds upon its earlier NINT (no-insulation) approach, which enhances magnet durability and efficiency. These innovations help reduce reactor size and cost, accelerating the path toward commercial fusion power plants.
Fusion Energy’s Strategic and Economic Impact
The development of fusion technology is drawing attention from policymakers and industry leaders.
At the CERAWeek energy conference in March 2025, Virginia Governor Glenn Youngkin emphasized the importance of accelerating fusion energy initiatives to maintain U.S. leadership in the global energy sector.
He highlighted concerns about international competition, particularly from countries like China, reinforcing the strategic significance of projects like CFS’s ARC power plant in advancing national energy innovation.
Next Steps in Reactor Assembly
The installation of the cryostat base required extensive inspection upon arrival, taking over a week to confirm it was undamaged during transit.
Once unboxed and prepared, the component was placed onto precision-positioned bolts in the reactor hall and secured using high-strength grout. This marks the first major component of the tokamak structure, with three additional key parts set for installation by early next year.
Following the completion of construction, CFS will enter the commissioning phase, ensuring that all systems function as expected. “This is the first of its kind,” Creely noted. “There’s not just like an on button and it turns on.”
