The U.S. has ambitious plans to triple the capacity of its nuclear power plants by 2050, but that goal might hit a roadblock if plant operators can’t buy fuel at reasonable prices. Prices for yellowcake, a form of unrefined uranium, are up 75% in the last five years, according to the U.S. Energy Information Administration. Further complicating matters, the U.S. doesn’t have significant resources within its borders—unless you consider the ocean.

The ocean has over 4 billion metric tons of uranium in it, enough for 50,000 years or so. 'It’s like a thousand times more than all identified hard rock mines combined,' Jeff Green, founder and CEO of the clean tech startup Fluxnium, told TechCrunch. Fluxnium thinks it has solved the problem of how to extract uranium from seawater using technology developed at U.S. Department of Energy national labs.

Green’s timing is good, but perhaps not surprising. He’s a repeat founder, having helped launch Stamps.com in 1996, desalination startup NanoH2O in 2005, and carbon removal startup 1PointFive in 2020. He has a nose for where the world is going, and he thinks uranium presents a big opportunity.

Fluxnium’s technology uses specially made polymer fibers that attract the uranium that’s dissolved in seawater. The company licensed the chemistry from the Department of Energy, and it has continued to work on the production and configuration of the fibers themselves. The key has been to increase the surface area of the fibers, Green said. When the technology was demonstrated at a national lab, it could extract uranium at more than $200 per pound, which is more than twice the price of Western suppliers today. But by increasing the surface area, Fluxnium has been able to draw more uranium out of the water, bringing costs down.

While uranium isn’t rare, as elements go, uranium mines aren’t plentiful or evenly distributed. 'If you’re in the West, two-thirds, three-quarters of the world’s uranium supply comes from Kazakhstan, Uzbekistan, Russia, Namibia, Niger, China. There’s geopolitical risk,' Green said. Fluxnium’s technology could potentially reduce these risks, making nuclear power more sustainable and less dependent on politically volatile regions.