Cambridge Heavy Industries, a startup based in Cambridge, Massachusetts, is developing a compact fusion device that can fit on a tabletop. The company has been operating in stealth mode from a small lab near MIT, where co-founder and CEO Yun Kai provided an exclusive look at their technology during a video call.
Kai stated, "We purposely built a small modular reactor. It’s tiny, it’s benchtop. Because it’s small, it makes everything easier." The compact design allows for rapid experimentation, enabling 50 to 80 experiments per day. The data from these experiments will be used to optimize the design through AI simulations.
Recently, Cambridge Heavy raised $6.2 million in a seed funding round led by Azolla Ventures, with participation from Overlay, Neta Foundation, P3A, MassCEC, and the Rothrock family.
The fusion reactor utilizes lasers to compress a fuel target, similar to a previous experiment that demonstrated controlled fusion reactions producing more energy than consumed. Unlike other designs, Cambridge Heavy’s approach minimizes the number of lasers required for ignition, using two main lasers that create concentric rings of light to compress the fuel target.
As the compression wave reaches the center of the target, a laser ignites the target, generating heat and a magnetic field, leading to fusion. Kai noted that their design achieves high pressures with relatively low laser power, a concept developed in the lab of MIT chemist Keith Nelson.
Cambridge Heavy plans to develop a power plant based on this concept within the next decade, which will be larger than the current prototype but smaller than traditional fusion power plants. The planned facility will be approximately the size of two basketball courts and will test the feasibility of generating sufficient energy for a power plant.
Before establishing the power plant, the company intends to use its smaller devices to produce tritium, a rare hydrogen isotope essential for fusion power plants. Currently priced at around $30,000 per gram, tritium is scarce, with only about 40 kilograms available globally. A study indicates that the fusion industry could face a shortfall of 28 kilograms by 2054 without new sources, valued at approximately $840 million.
Fusion startups are working on fuel systems to ensure self-sufficiency in tritium supplies, though they may require occasional replenishment, a process that could take up to 10 years. This timeline presents Cambridge Heavy with potential revenue opportunities as it develops its power plant.