Fusion startup Inertia Enterprises says it has found a way to cut the time it takes to make fuel pellets from days to just minutes.
By reducing fuel fill times, Inertia says it has broken one of the 10 hurdles it must overcome to realize the first stage of its commercial power plant ambitions. The startup revealed its process exclusively to TechCrunch.
Advancement was not guaranteed. Investors gave Inertia $450 million on the basis that the technology developed at the National Ignition Facility (NIF) could be commercialized. NIF is an elaborate scientific experiment that requires painstaking care and nutrition to operate. At NIF, producing fuel pellets can take more than a week and cost a lot of money. That’s not a great recipe for running a profitable business.
“But when you actually double-click on it, you’re like, wait a minute, we only make a few a year,” Inertia co-founder and CEO Jeff Lawson told TechCrunch. “I put on my commercial hat and thought, ‘Wait a minute, I know the word for this, prototype.'”
At Inertia, the team set out to turn these prototypes into something that could be mass produced. “That’s why we hire from companies like Apple,” he said. “There are a lot of industrial engineers who are like, ‘Okay, we’ve got to figure out a way to multiply this by a billion times in a factory.'”
But NIF’s fuel pellets are far from iPhones. The outside is a spherical diamond shell, and just inside is a thin layer of frozen deuterium and tritium, the isotopes of hydrogen that fuel fusion reactors. Inside the crystalline layer, a gas mixture of deuterium and tritium exists. Each solid layer should be as close to a perfect sphere as possible.
These fuel pellets are encased in a gold casing known as a phorraum, which converts the laser energy into X-rays and compresses the fuel pellets inside. If all goes to plan, that compression causes the atoms to fuse and release energy. However, even a small spherical defect can interrupt the ignition process, preventing the fusion reaction from reaching its full potential.
Inertia needed to condense the process to a point where it made commercial sense without significantly departing from the physics discovered at NIF.
“What if we tried to do it faster?” Lawson said. The team had a head start. Annie Critcher, co-founder and principal scientist at Inertia, designed the first fusion experiment at NIF to emit more power than it consumes.
After several rounds of development, the startup was able to grow crystals in about 30 minutes, whereas NIF could take up to a week. In total, a single fuel pellet can be made in about two to three hours, allowing the process to be scaled up to industrial scale. Inertia developed the process with support from Lawrence Livermore National Laboratory’s NIF, a public-private partnership.
However, inertia has advantages over NIF. The startup plans to use a laser four times more powerful than the one currently at NIF, so it can tolerate more imperfections in the fuel pellets. This also helped speed up the manufacturing process.
“We actually have a lot of margin,” Lawson said. “That’s our strategy: make the driver and laser bigger and have plenty of headroom in all the other parts of the system.”
Reducing fuel fill time has the knock-on effect of reducing the amount of tritium that needs to maintain inertia at all times. Tritium is a radioactive substance, so care must be taken when handling it. It’s also currently extremely expensive, costing about $30,000 per gram, and only about 25 kilograms of it are stockpiled worldwide, according to Science.
Inertia, like many fusion startups, plans to produce its own tritium with the help of fusion reactions, but it still needs some inventory to get started. Furthermore, by reducing manufacturing time, inventory can be kept small. Inertia expects a full-scale commercial power plant to use 10 fuel pellets per second.
“By reducing the wait time for this step, we have a smaller facility, faster overall, and more efficient overall,” Lawson says.
If you buy through links in our articles, we may earn a small commission. This does not affect editorial independence.
