Company Spotlight: Fluxnium Builds Uranium From Seawater

Fluxnium is a Santa Monica startup building a domestic uranium supply around material science and aquaculture infrastructure. Founder and CEO Jeff Green and co-founder and Executive Chairman Jim McDermott are developing adsorbent fibers designed to recover uranium dissolved in seawater.

The company matters because nuclear energy has two supply problems at once. Demand for reliable, carbon-free generation is rising, while U.S. operators still depend heavily on imported uranium. Fluxnium is testing whether an enormous ocean resource can become useful inventory without opening a conventional mine.

The science has already crossed the line from theory to recovery. The commercial question is harder. Fluxnium must make adsorption, time in the water, fiber reuse, uranium recovery, and marine operations add up to a commodity-level cost.

About Fluxnium

Fluxnium was incorporated in Delaware in 2026 and operates from Santa Monica, California. The company is building high-surface-area fiber that passively binds uranium ions present in seawater at roughly three parts per billion.

The core chemistry comes from Department of Energy research, while Fluxnium is developing its own fiber production and configuration. According to TechCrunch, the company plans to expose fibers to seawater for roughly 30 to 60 days, retrieve them, recover the uranium as yellowcake, and reuse the lines across multiple cycles.

The operating model borrows from seaweed and mussel farms. Longlines provide surface area and contact with moving seawater, replacing ore excavation with a marine collection system. That does not remove industrial complexity. It moves the hard work into materials, ocean operations, recovery chemistry, and processing.

Why Uranium From Seawater Matters

Pacific Northwest National Laboratory estimates that the oceans contain more than four billion tons of uranium. At current demand, the resource could support nuclear generation for centuries. Its scale is strategically interesting precisely because it is geographically distributed rather than concentrated in a mine or exporting country.

The United States still has a concentrated supply-chain exposure. The U.S. Energy Information Administration reported that U.S. civilian nuclear operators bought 46.9 million pounds of uranium in 2025 and sourced 93% from foreign suppliers. Domestic material represented 7% of deliveries.

Fluxnium's premise is that a repeatable ocean system could add another domestic pathway. The potential advantages include no mine tailings, less groundwater disruption, and a resource that does not depend on discovering a new ore body. Those remain operating hypotheses until pilots establish recovery rates, durability, permitting requirements, and full-cycle costs.

The Material Is the Business Model

Seawater abundance can be misleading. A vast total resource does not help if each kilogram of fiber collects too little uranium or loses performance too quickly. Adsorbent capacity, selectivity against other dissolved metals, exposure time, regeneration chemistry, and reuse cycles all determine the delivered cost.

Public research has demonstrated uranium recovery from natural seawater, but older economics remained well above market prices. TechCrunch reported that a prior national-laboratory demonstration exceeded $200 per pound. Fluxnium says its subsequent material and manufacturing work has lowered costs and projects parity with conventional mining, though it has not published a current independently verified cost per pound.

This makes fiber manufacturing and reuse more than technical details. They are the margin structure. A small improvement in surface area or degradation can compound across longline length, days at sea, retrieval cycles, and processing volume.

Leadership Built Around Materials Commercialization

Jeff Green brings experience moving advanced materials into industrial markets. He founded NanoH2O, which developed nanocomposite membranes for water treatment and was acquired by LG Chem in 2014. Fluxnium's official biography says NanoH2O reached more than 300 installations across 40 countries within three years.

Jim McDermott is a founding and managing partner of Rusheen Capital Management. His investing and company-building work spans water, carbon capture, fuels, and industrial climate technologies. That background fits a startup whose challenge is not publishing another lab result, but financing equipment, field trials, and industrial scale.

The company has not published a full operating roster, culture program, careers page, or current openings. Hiring momentum therefore cannot be verified as a growth signal. The visible signal is capital deployment into development, pilot testing, and scale-up.

What the $7M Seed Round Must Prove

Fluxnium raised a $7 million Seed round led by Congruent Ventures. Constellation Technology Ventures and Active Impact Investments also participated.

The investor mix connects climate technology, advanced materials, and nuclear operations. Constellation's participation is strategically relevant, but it carries an explicit limit: the investment is not a fuel-purchase commitment. Fluxnium has industry attention, not guaranteed demand.

The next evidence should be operational. Investors and prospective customers will need adsorption per kilogram of fiber, recovery yield, reuse degradation, marine reliability, processing cost, and a route from pilot lines to commercial volume. Those measures will decide whether Fluxnium is a promising materials company or the beginning of a new uranium supply chain.

Fluxnium is not trying to prove the ocean contains uranium. It is trying to make three parts per billion behave like infrastructure.