Clean tech startup Fluxnium found a way to tap 50,000 years’ worth of nuclear fuel

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.

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. 

Those concerns have been bubbling under the surface of the nuclear industry for decades. “Now with this new nuclear renaissance?” he said. “If demand comes the way it’s being projected, we’re structurally short uranium.”

But those concerns would evaporate if someone could find a way to economically extract uranium from seawater.

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.

Much of the costs are wrapped up in manufacturing the fibers and deploying them in the ocean.

Here’s how it works. After the material has been made into long, braided fibers, they’re hauled out to sea and hung off buoys, similar to the way that seaweed is farmed. After 30 to 60 days at sea, they’re brought ashore, and the uranium is extracted without any toxic tailings left behind. Each line can be reused several times over.

Once the uranium is eluted from the fibers, it is purified into yellowcake. “Then we sell that just as any other mine into the supply chain,” Green said. 

“None of the components of this process are anything novel. It’s all been done in different ways,” he said. “Our job is to drive cost out of the supply chain, keep working through all the stages of the process to make it as low cost as possible.”