Fluxnium, Inc. announced a $7 million seed round led by Congruent Ventures, with participation from Constellation Technology Ventures and Active Impact Investments, to commercialize technology that extracts uranium dissolved in seawater. The Los Angeles-based company says its proprietary high-surface-area fiber, developed with a leading U.S. national laboratory, passively adsorbs uranium as seawater moves past it. Fluxnium said the technology could provide a domestic and sustainable uranium source for civilian nuclear fuel and defense supply chains, with proceeds funding further development, pilot testing and scale-up. The company plans to deploy the fiber on offshore longline systems, retrieve and process it, and redeploy it. Fluxnium says ocean capacity can expand by adding fiber rather than developing new mines, avoiding tailings and ground-water concerns associated with conventional mining. Constellation Technology Ventures said its investment is not a fuel-purchase commitment.