Cambridge Heavy Industries has been quietly building a desktop fusion device
Fusion power startup Cambridge Heavy Industries is building a small, laser-powered fusion device to fuel the coming wave of fusion power plants.
Key points
- Cambridge Heavy Industries built a benchtop fusion device in a small lab near MIT.
- The startup raised a $6.2 million seed round led by Azolla Ventures.
- It plans to make tritium before developing a power plant in about a decade.
A startup in Cambridge, Massachusetts, has been quietly developing a fusion device small enough to sit on a tabletop. Cambridge Heavy Industries has operated in stealth out of a small lab near MIT, and co-founder and CEO Yun Kai gave TechCrunch an exclusive look at the technology.
The company recently raised a $6.2 million seed round led by Azolla Ventures, with participation from Overlay, Neta Foundation, P3A, MassCEC, and the Rothrock family. Kai said the small size lets the company experiment and iterate quickly.
How the device works
Cambridge Heavy's reactor uses lasers to compress a fuel target, similar to the experiment that proved controlled fusion reactions could produce more power than they consume. Unlike other inertial confinement designs, it minimizes the number of lasers needed to spark fusion.
The system uses two main lasers to drive ignition. One is split into beam lines that deliver light in concentric rings, timed to hit the flat, round fuel target successively from the outside in. As the shock wave reaches the center, a laser fires on the target, generating heat and producing a magnetic field; with the right pressure and heat, fusion occurs.
We purposely built a small modular reactor. It’s tiny, it’s benchtop.
— Yun Kai
Tritium and future plans
Kai said the design generates high pressures with relatively low laser power. The concept emerged from the lab of Keith Nelson, a chemist at MIT, where researchers used laser pulses to study materials under extreme conditions and realized they were approaching fusion-ready conditions.
In about a decade, Cambridge Heavy plans to develop a power plant from the concept, which Kai said should be about the size of two basketball courts. Before that, it plans to use smaller-scale devices to make tritium, a rare hydrogen isotope that sells for around $30,000 per gram today.
