Fluxnium Raises $7M for Uranium From Seawater

The raw material beneath Fluxnium's plan is vast; the useful concentration is almost absurdly small. Seawater contains roughly three parts per billion of uranium, forcing the company to turn surface area, deployment time, fiber reuse, and recovery chemistry into the economics of a new domestic fuel source.

Fluxnium announced a $7 million Seed round led by Congruent Ventures, with participation from Constellation Technology Ventures and Active Impact Investments. The Santa Monica company will use the financing for further development, pilot testing, and scale-up of fibers designed to collect uranium from seawater.

That is the commercial wager inside the funding announcement. The ocean's uranium inventory is not in doubt. The hard part is collecting a commodity dispersed through moving salt water at a cost that can compete with mining.

What Happened

Fluxnium's September 21 announcement describes high-surface-area fiber developed with a U.S. national laboratory. The company plans to suspend that material from offshore longline systems, allow it to adsorb uranium, then retrieve, process, and redeploy the fibers.

An SEC Form D shows Fluxnium sold $6,999,998 of equity to three investors, with the first sale recorded on May 5. Jeff Green signed the filing as CEO; Jim McDermott and Congruent partner Kevin Kopczynski also appear as directors or executive officers. The financing closed before the public announcement and before TechCrunch reported that the company was emerging from stealth.

Green founded the company and serves as CEO. His operating history includes founding membrane-technology company NanoH2O, which LG Chem acquired in 2014. McDermott, Fluxnium's co-founder and Executive Chairman, is also a founding and managing partner of Rusheen Capital Management.

How Fluxnium's Seawater Process Works

Fluxnium is building on a line of public research that uses amidoxime-based materials to bind uranium ions in seawater. Pacific Northwest National Laboratory has demonstrated that acrylic fibers can recover uranium from natural seawater and produce yellowcake, the concentrated uranium product used earlier in the nuclear-fuel cycle.

Fluxnium has licensed Department of Energy chemistry and is developing its own fiber production and configuration, according to TechCrunch. The company expects longlines to remain in the water for roughly 30 to 60 days before the fibers are collected and processed. It says those lines can be reused several times.

The physical model resembles seaweed or mussel farming more than a mine. Longline systems create exposure to large volumes of seawater while avoiding ore excavation, tailings, and groundwater disruption associated with conventional uranium mining. Fluxnium says its system can reach cost parity with conventional mining, but it has not disclosed a current independently verified cost per pound.

Why the Economics Are the Company

The ocean holds more than four billion tons of uranium, according to PNNL. At today's demand, that is enough material for centuries. Yet abundance across the whole ocean does not erase the concentration problem at a particular fiber.

Prior national-laboratory research helps define the operating variables. Adsorbent capacity, selectivity against other dissolved metals, time in the water, marine durability, and the number of reuse cycles all affect the delivered cost. PNNL researchers have found that extraction performance can decline over repeated cycles, which makes regeneration and durability part of the unit economics rather than secondary engineering details.

TechCrunch reported that an earlier national-laboratory demonstration cost more than $200 per pound of uranium, at least twice prevailing Western supplier prices at the time. Fluxnium says its material and manufacturing work has lowered the cost since then. Until pilot data supplies a current figure, that progress remains a company claim rather than demonstrated cost parity.

The Domestic Fuel-Supply Argument

The financing arrives while the United States remains heavily dependent on imported uranium. The U.S. Energy Information Administration reported that U.S. civilian nuclear operators bought 46.9 million pounds of uranium in 2025, and 93% came from foreign sources. Domestic uranium accounted for 7% of deliveries.

That dependence gives Fluxnium's process strategic value beyond the size of the ocean resource. A working domestic source could diversify supply without requiring a conventional ore body, and a modular longline system could introduce a different scaling path from opening a mine. Those advantages still depend on marine permitting, operations, processing throughput, and costs that Fluxnium has not yet disclosed.

Constellation Technology Ventures adds a direct industry connection. The venture arm belongs to one of the largest nuclear operators in the United States, and Constellation executive Jason Murphy framed uranium-supply innovation as relevant to reliable nuclear generation. The announcement also draws an important boundary: Constellation's participation is an investment only, not a commitment to purchase Fluxnium's future fuel.

What the Investor Mix Signals

Congruent Ventures led the round from the climate-technology side. Its partner Kevin Kopczynski said Fluxnium combines advanced materials with scalable ocean deployment, and his position on Fluxnium's board gives the firm a continuing governance role.

Constellation Technology Ventures brings the perspective of a potential downstream industry, while Active Impact Investments adds another climate-focused investor. Together, the syndicate connects materials commercialization, climate infrastructure, and nuclear-fuel demand without turning that interest into guaranteed revenue.

The $7 million now has a narrow job: move the story from laboratory chemistry toward repeatable open-water performance. Useful evidence will include adsorption per kilogram of fiber, recovery yield, reuse degradation, full-cycle cost, marine-operating reliability, and a credible route from pilot equipment to commercial volumes.

Fluxnium does not need to prove that uranium exists in seawater. It needs to prove that a microscopic concentration can behave like infrastructure.