Pacific Fusion made a splash in October when it emerged from stealth with a $900 million Series A and a founding team led by a scientist who is most widely known for his work on the Human Genome Project.
Now, the startup is revealing the physics that underpin its plans to build a fusion reactor.
“We’re publishing our detailed technical roadmap,” Will Regan, co-founder and president of Pacific Fusion, told TechCrunch. “We lay out the details of the system that’s going to let us get 100x the gain of what the [National Ignition Facility] can do at about one-tenth the cost.”
The bet is a long term one: the company said that the first commercial reactor is about a decade away.
Pacific Fusion follows a similar path to fusion power as the National Ignition Facility, the Department of Energy research program that was the first to demonstrate that a controlled fusion reaction could generate more power than was required to ignite it. The approach is called inertial confinement, which means the fuel is squeezed to the point where atoms start fusing with one another, releasing tremendous amounts of power in the process.
But where the NIF uses lasers to compress the fuel pellet, Pacific Fusion plans to send a massive pulse of electricity into a target, generating a magnetic field that’ll cause it a shell encasing the fuel to compress in about 100 nanoseconds.
Generating the electricity will be 156 impedance-matched Marx generators (IMG), or pulser modules, a power source invented by co-founder Keith LeChien and others. Together, the pulser modules produce 2 terawatts for 100 nanoseconds. “That’s about 4x the average power of the U.S. grid,” Regan said.
Each pulser module contains repeating elements. There are 32 “stages,” which are essentially rings of metal surrounded by ten “bricks.” Each brick consists of a switch and a capacitor, or a short-term energy storage device.
Ensuring that the electricity from each brick reaches the fuel pellet at the same time requires exact timing — a single capacitor will dump all its energy in only about 100 nanoseconds, Regan said. “Our version of the Marx generator, the IMG, is something that is inherently fast pulse,” he said. “That timing is consistent throughout the entire system because we synchronize it.”
Once the bricks discharge, the electricity will travel down cables from each pulser module to the reaction chamber, which will be kept at vacuum. There, the surges will converge around the target, applying electromagnetic force that will squeeze it until fusion occurs.
So far, Pacific Fusion is “several months ahead of schedule,” Regan said, having developed the necessary simulation models and built completed prototypes of the bricks and stages. That allows the company to unlock the next portion of their $900 million funding round, which will go toward building a complete pulse module, or IMG.
“Once we do that, we basically carbon copy it 150 times to make a whole system,” he said.
The funding round, while massive by Series A standards, isn’t accessible all at once. It’s built to pay out serially as the company hits certain milestones. Large rounds doled out in tranches are common in biotech, though not in other sectors. Credit for the startup’s funding model, Regan said, goes to investors at General Catalyst, co-founder and CEO Erik Lander, and co-founder and COO Carrie von Muench, who were all familiar with its use in biotech.
Pacific Fusion also recently hired Sachin Desai as general counsel, the company exclusively told TechCrunch. Desai had previously served in the same capacity at a competitor, Helion.
Fusion doesn’t have the same regulatory concerns as fission, and it received some added clarity with the passage of the Advance Act in July 2024, which lays out a regulatory framework for fusion that’s different from fission.
But since there are no commercial fusion reactors in existence, there are still many unanswered questions.
“It’s just important that we’re always in the room and we’re part of the conversation as rules are made,” Regan said. “It’s going to be an ongoing process.”
