Commonwealth Fusion Systems (CFS) marked a significant achievement with the installation of a crucial component for its Sparc demonstration reactor. The newly installed component is a 24-foot wide, 75-ton stainless steel circle, known as the cryostat base. This element forms the foundation of the tokamak, a doughnut-shaped core of a fusion reactor that CFS aims to make the first to generate more energy than it consumes. The base was manufactured in Italy and transported to the CFS site in Devens, Massachusetts.
Alex Creely, the director of tokamak operations at CFS, informed TechCrunch that this marks the initial segment of the fusion machine’s physical construction. The site has been under development for over three years as the company builds the infrastructure and machinery necessary to support the reactor’s core. Creely stated that this step represents a transition into a new phase of the project where the focus is shifting from constructing an industrial facility to building the actual tokamak itself.
CFS is among various startups venturing into the field of fusion power, which offers the potential for providing large amounts of pollution-free electricity from hydrogen fuel sourced from seawater. Investors are increasingly relying on this technology to fulfill future energy demands, which are increasing due to the proliferation of electric vehicles and data centers. Backed by Bill Gates’s Breakthrough Energy Ventures and other investors, CFS is considered one of the top contenders to prove the commercial viability of fusion power. In December, the company announced the location of its first commercial-scale reactor outside Richmond, Virginia.
Sparc is projected to be operational by 2027. If successful, it could be the first tokamak to produce more power than it requires to operate. To date, only the Department of Energy’s National Ignition Facility has managed to achieve scientific break-even during a series of successful experiments, the initial one occurring in December 2022. Unlike the NIF’s reactor, which uses lasers to compress a fuel pellet to fusion conditions, CFS’s tokamak employs magnets to confine and compress plasma at temperatures exceeding 100 million degrees Celsius into a tight doughnut shape until fusion occurs.
The tokamak utilizes superconducting magnets to create the necessary powerful magnetic fields to control the plasma. These magnets must be cooled to –253 degrees Celsius using liquid helium. The cryostat functions much like a thermos, insulating against ambient temperatures to maintain these frigid conditions. Creely explained that the cryostat base acts like the bottom of a thermos.
Upon receiving the cryostat base, the CFS team had to unbox and examine it thoroughly before installation, a process that took several days to remove the shipping material and another week to ensure it was undamaged. The base was subsequently moved to the tokamak hall, where bolts had been precisely placed in the concrete foundation. Creely described the process of securing it with grout.
Work on the other three significant components of the tokamak is progressing simultaneously to integrate them into their final arrangement by the end of this year or early next year. Following assembly, CFS will undertake the commissioning process to verify the proper integration and functionality of all components, which Creely noted, is a complex endeavor without a simple start button.
