Fluxnium Secures $7 Million Seed Round to Build a New Domestic Supply of Uranium

Fluxnium’s seed round funds pilot-scale deployment of its seawater uranium adsorption fibers to support future domestic nuclear fuel supply.

Rhea-AI Summary

Fluxnium, a uranium-from-seawater startup, raised a $7 million seed round on September 21, 2026 to advance its fiber-based adsorption technology.

The round was led by Congruent Ventures, with participation from Constellation Technology Ventures, the venture arm of Constellation (NASDAQ: CEG), and Active Impact Investments. Fluxnium plans to use proceeds for technology development, pilot testing and scale-up of its high-surface-area fiber, developed with a U.S. national laboratory, which passively adsorbs dissolved uranium from seawater using longline marine systems similar to seaweed and mussel farms.

Positive

• $7 million seed funding raised to develop and scale uranium-from-seawater technology
• Round led by Congruent Ventures with participation from Constellation Technology Ventures and Active Impact Investments
• Proceeds earmarked for development, pilot testing and scale-up of adsorption fiber platform

Negative

• None.

Market Context

The Jul 16 CTV investment announcement recorded a 2.46% 24-hour decline in CEG; that prior nuclear-d...

Analysis

The Jul 16 CTV investment announcement recorded a 2.46% 24-hour decline in CEG; that prior nuclear-development investment was a relevant precedent for CTV's participation in Fluxnium's seed round.

Key Figures

Seed round: $7 million Uranium import reliance: More than 90% Nuclear generation projection: 2.5X +1 more

Seed round

$7 million

Funding led by Congruent Ventures with CTV participation

Uranium import reliance

More than 90%

United States uranium supply

Nuclear generation projection

2.5X

Projected global nuclear power generation increase in the next 15 years

Seawater uranium supply

Roughly 1,000 times

Compared with currently identified terrestrial deposits

Historical Context

1 past event · Latest: Jul 16

1 event

1. Jul 16

   Strategic nuclear investment

   24h Move

   -2.5%

   CTV invested in Blue Energy, a nuclear developer, to support small modular reactor deployment.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

adsorption, nuclear fuel cycle, tailings

3 terms

adsorption technical

"Adsorption from seawater addresses those concerns"

Adsorption is a physical or chemical process where atoms, ions or molecules stick to the surface of a solid or liquid rather than entering its bulk, different from absorption which soaks into the material. Think of dust clinging to a tabletop: the particles collect on the surface. Investors encounter this term in contexts like drug formulations, catalysts, filtration, sensors and environmental cleanup because surface interactions can determine product performance, manufacturing yield, regulatory compliance and cost.

nuclear fuel cycle technical

"underpins both the civilian nuclear fuel cycle"

The nuclear fuel cycle is the full supply chain that turns raw uranium into usable reactor fuel, manages its use in power generation, and handles spent fuel and any recycling or disposal. Think of it like the path from coffee beans to a brewed cup and the leftover grounds — each step (mining, conversion, enrichment, fabrication, reactor use, storage or reprocessing) affects cost, regulatory risk, supply security and long-term liabilities, all of which influence the value and prospects of companies involved.

tailings technical

"with no tailings or ground water concerns"

Tailings are the leftover rock, water and fine particles produced when ore is crushed and processed to extract metals or minerals. Think of them as the muddy residue from a kitchen filtering process: they are stored in ponds or engineered dams and can carry chemical contaminants, so they matter to investors because they represent ongoing cleanup costs, regulatory liabilities and operational risks that can affect a mining company’s finances and reputation.

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Breakthrough High Efficiency Fiber Technology Enables Uranium Adsorption from Seawater Rather Than Mined from Rock

LOS ANGELES, Sept. 21, 2026 /PRNewswire/ -- Fluxnium, Inc. (Fluxnium), a pioneer of domestic uranium supply adsorbed from seawater, today announced a $7 million seed round led by Congruent Ventures, with participation from Constellation Technology Ventures, the venture investing organization within Constellation (NASDAQ: CEG), the nation's largest producer of reliable and clean energy, and Active Impact Investments, Canada's largest climate technology seed fund. The funding catalyzes the commercialization of a new secure source of uranium, the critical mineral that underpins both the civilian nuclear fuel cycle and the defense supply chain. Proceeds will go towards further development, pilot testing and scale-up of Fluxnium's technology platform.

The largest uranium supply on Earth is not underground; it is dissolved in the ocean. Seawater holds centuries' worth of supply for the global uranium market — roughly a thousand times more than all currently identified terrestrial deposits combined. The challenge is that dissolved uranium exists at very low concentrations. Fluxnium addresses this challenge through its proprietary high-surface-area fiber, recently developed with a leading U.S. national laboratory, that passively adsorbs uranium as seawater moves past it.

"The United States imports more than 90% of its uranium supply at a time when nuclear power is increasingly seen as a solution to growing demand for electricity driven by economic growth," said Jeff Green, CEO and Founder of Fluxnium. "Fluxnium is developing a new domestic and sustainable supply of uranium, passively adsorbed from seawater on proven offshore infrastructure — at a cost projected to compete with conventional mining, with no tailings or ground water concerns."

Fluxnium's fiber deploys on longline systems in open water — the same passive marine infrastructure proven by seaweed and mussel farms — then is retrieved, processed, and redeployed. With accelerating demand for nuclear power, plant operators are very interested in cost-competitive and sustainable fuel supply beyond uranium mining.  Traditional uranium production projects can require significant time, capital investment and regulatory review before reaching commercial operation. Adsorption from seawater addresses those concerns, and the approach expands production by deploying additional fiber rather than developing a new mine.

"With the current uranium market dynamics, there is a new path to making the ocean one of the lowest-cost sources in the world," said Kevin Kopczynski, Partner at Congruent Ventures. "Congruent is excited to support Fluxnium as it unlocks the ocean's potential as a major contributor to a diverse and robust domestic nuclear fuel supply chain."

"Innovations that could expand domestic sources of uranium are important areas of research for the nuclear energy industry," said Jason Murphy, Vice President of Nuclear Fuels, Constellation. "Fluxnium's technology has the potential to broaden future fuel supply options and support growing demand for clean, reliable nuclear energy."

"With global nuclear power generation projected to increase 2.5X in the next 15 years, Fluxnium is the future of uranium supply with clean, lower cost ocean adsorption displacing the environmental damage from mining and tailings," said Tom Boddez, General Partner at Active Impact Investment. "We have strong conviction that Jeff and co-founder Jim McDermott, with their prior successes taking hardtech ideas to commercial reality, are the ideal team to seize this opportunity."

About Fluxnium

Fluxnium is building a new domestic supply of uranium — adsorbed from seawater rather than mined from rock. Using high-efficiency adsorbent fiber developed with a leading U.S. national laboratory, Fluxnium passively adsorbs uranium already dissolved in seawater at a cost projected to match conventional mining. With the ocean containing centuries of uranium supply, capacity grows by deploying more fiber — becoming a production decision rather than a long-term capital investment for mine construction. And because there is no mine, there are no tailings or ground water concerns, which eliminates the slowest and most contested steps of conventional permitting. Deployed on the same infrastructure proven in offshore aquaculture, Fluxnium's mission is to make the ocean the lowest-cost source of uranium in the world. For more information, visit https://fluxnium.com

About Congruent Ventures

Congruent Ventures is an early-stage, climate-focused venture capital firm founded in 2017. The firm backs North American founders from formation through Series A across five sectors: Energy Abundance, Agriculture + Food, Industry + Efficiency, Mobility + Built Environment, and Resilience + Restoration. Congruent manages over $1B in AUM across three early-stage funds and one later-stage fund, and has backed 60+ companies to date. Learn more at congruentvc.com.

About Constellation Technology Ventures

Constellation Technology Ventures (CTV) is the venture investing organization within Constellation, the United States' largest producer of clean, carbon-free energy and a leading supplier of energy products and services to businesses, homes, community aggregations and public sector customers. CTV invests in companies exploring innovative energy technologies and business models, building a portfolio that represents a broad range of development stages and technology types. CTV's participation represents a venture investment in the continued development of Fluxnium's technology and does not constitute a fuel-purchase commitment at this time.

About Active Impact Investments

Active Impact Investments is Canada's largest climate tech seed fund, managing three funds and $180M in assets from Vancouver, British Columbia. We are helping build the future of production and consumption by investing in early-stage companies that solve the most urgent environmental challenges while achieving venture scale. We look for capital-efficient, market-ready businesses that deliver cheaper, better solutions with immediate customer ROI. Beyond capital, we dedicate our time to the areas founders need most: sales, talent and fundraising, supported by a global network of operators and investors. Active Impact is a Certified B Corp.

Media Contact

Jeff Green

CEO & Founder

info@fluxnium.com

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SOURCE Fluxnium Inc.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How does Fluxnium’s technology obtain uranium from seawater?

Fluxnium uses a proprietary high-surface-area fiber, developed with a leading U.S. national laboratory, that passively adsorbs uranium as seawater flows past it. The fiber is deployed on longline systems in open water, retrieved after adsorption, processed to recover uranium, and then redeployed.

What infrastructure is used to deploy Fluxnium’s uranium adsorption fibers?

The company deploys its fibers on longline systems in open water, using the same type of passive marine infrastructure proven by seaweed and mussel farms, which allows scaling production by adding more fiber rather than building new mines.

What market need is Fluxnium aiming to address with this seed funding?

Fluxnium is targeting the need for a domestic, sustainable and cost-competitive uranium supply as nuclear power demand grows and the United States imports more than 90% of its uranium. The company said its seawater adsorption approach aims to compete with conventional mining without tailings or groundwater concerns.