CFS begins preparing a home for our 100 million degree fusion plasma [View all]
https://blog.cfs.energy/cfs-begins-preparing-a-home-for-our-100-million-degree-fusion-plasma/

May 14, 2026 by Alex Graziano [Senior Content Marketing Manager]
The second half of the vacuum vessel for our
SPARC demonstration fusion machine has arrived, allowing us to begin equipping it and its counterpart to host the most intense conditions in the solar system. Weve now begun the hard work of fitting out the vacuum vessel halves for use by measuring them carefully, using those measurements to precisely make the components thatll face the fierce plasma temperatures, and adding the diagnostic equipment to control and understand SPARC.
The vacuum vessel is the 96-ton, donut-shaped steel chamber at the heart of SPARC. Once weve fully equipped the two halves, welded them together, and begun SPARC operations, our vacuum pumps will make it as airless as outer space. When SPARC operations begin in 2027, well puff in a bit of fusion fuel and use radio waves to heat it into an energetic cloud of particles called a plasma. Well heat that plasma to 100 million degrees Celsius, holding it in place with powerful magnets so it fuses and releases more energy from fusion than it took to heat it.
This net fusion energy milestone, called Q>1 in scientific circles, is a crucial step to prove our fusion energy approach works.
With
SPARCs cryostat base already installed, and
two of our D-shaped toroidal field (TF) magnets now in place more to come soon SPARC is nearly 75% complete and is starting to look like an actual tokamak.
Eventually, each vacuum vessel half will be housed within a set of nine D-shaped toroidal field magnets arranged in a semicircular array, then each of those assemblies will be mated together. But before any of that can happen, both halves of the vessel need to be inspected, cleaned, measured, and outfitted with plasma-facing components and diagnostic systems.