A clean tech startup called Fluxnium has cracked a problem that could reshape nuclear energy's future: extracting uranium directly from seawater at competitive prices. The ocean contains over 4 billion metric tons of dissolved uranium, enough to power the world's nuclear reactors for roughly 50,000 years. Using polymer fibers licensed from U.S. Department of Energy national labs, Fluxnium believes it can make seawater uranium extraction economically viable for the first time, addressing a critical bottleneck as demand for nuclear power surges.

Why Is Uranium Supply Becoming a Problem Now?

The U.S. has ambitious plans to triple its nuclear power capacity by 2050, but a major obstacle stands in the way: uranium prices have climbed 75% over the last five years, according to the U.S. Energy Information Administration. The problem isn't that uranium is rare as an element; it's that uranium mines are concentrated in a handful of countries, creating geopolitical risk. Most of the world's uranium supply comes from Kazakhstan, Uzbekistan, Russia, Namibia, Niger, and China. As tech companies race to build AI data centers and demand for nuclear power accelerates, this geographic concentration could become a serious constraint.

"If demand comes the way it's being projected, we're structurally short uranium," said Jeff Green, founder and CEO of Fluxnium.

Jeff Green, Founder and CEO, Fluxnium

Green is a repeat entrepreneur with a track record of spotting emerging opportunities. He co-founded Stamps.com in 1996, launched desalination startup NanoH2O in 2005, and started carbon removal company 1PointFive in 2020. His latest venture addresses a genuine supply-chain vulnerability in the nuclear industry at a moment when the sector is experiencing a renaissance driven by AI's insatiable appetite for electricity.

How Does Fluxnium's Seawater Uranium Extraction Work?

The technology relies on specially designed polymer fibers that selectively attract dissolved uranium from seawater. Fluxnium licensed the underlying chemistry from the Department of Energy and has spent years refining the production and configuration of the fibers themselves. The key innovation has been increasing the surface area of the fibers to extract more uranium per deployment, which directly reduces costs.

The process is surprisingly straightforward. After the material is braided into long fibers, they're deployed at sea and suspended from buoys, similar to how seaweed is farmed. The fibers remain in the water for 30 to 60 days, absorbing dissolved uranium. Once retrieved, the uranium is extracted from the fibers without generating toxic tailings. Each fiber can be reused multiple times, and the extracted uranium is then purified into yellowcake, the standard form sold into the nuclear fuel supply chain.

Steps to Understanding Fluxnium's Cost Reduction Strategy

• Initial Challenge: When the technology was first demonstrated at a national lab, uranium extraction cost over $200 per pound, more than twice the price of Western uranium suppliers at the time.
• Surface Area Optimization: Fluxnium increased the fiber surface area to draw more uranium from the water with each deployment, directly lowering the cost per pound extracted.
• Manufacturing and Deployment Focus: Much of the remaining cost is wrapped up in manufacturing the fibers and deploying them in the ocean, areas where Fluxnium continues to drive efficiency improvements.

Green emphasized that none of the individual components of Fluxnium's process are novel. "It's all been done in different ways," he explained. "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". This engineering-focused approach suggests the company is pursuing incremental improvements rather than relying on breakthrough chemistry.

Green

What Does This Mean for the Nuclear Industry?

Fluxnium's timing aligns perfectly with a broader nuclear renaissance in the U.S. Tech companies have backed multiple nuclear startups as they search for reliable, carbon-free electricity to power their AI data centers. The startup recently closed a $7 million seed round led by Congruent Ventures, with participation from Active Impact Investments and Constellation Energy, which operates the largest nuclear fleet in the United States.

If Fluxnium can achieve cost parity with traditional uranium mining, the implications are substantial. Seawater uranium extraction would eliminate geographic constraints on fuel supply, reduce geopolitical risk, and provide a virtually unlimited resource base for nuclear power expansion. This could be particularly important as AI's electricity demands continue to grow and utilities seek to meet those demands with carbon-free generation.

The company has been operating in stealth mode until now, focusing on developing and refining its technology before entering the market. With seed funding secured and backing from a major nuclear operator, Fluxnium is positioned to move toward commercialization and real-world deployment in the coming years.