Lasers could turn Kentucky's Cold War uranium stockpile into advanced reactor fuel

Thousands of yellow cylinders of depleted uranium sit on a pad outside the closed Paducah, Kentucky enrichment plant, a Cold War relic treated for decades as a waste-management liability. Global Laser Enrichment now wants to re-enrich those "tails" using lasers tuned to the light-absorption fingerprints of uranium's fissile isotope, as MIT Technology Review reported in a July 2026 feature on the project. If the plan works, the material corroding into a balance-sheet problem becomes a domestic feedstock for the advanced reactors that are supposed to define the next nuclear buildout.

Laser enrichment targets a specific behavior of uranium hexafluoride gas: a UF₆ molecule containing the fissile isotope U-235 absorbs light at a slightly different wavelength than one containing U-238. Photons at the right frequency can preferentially excite and separate the U-235-bearing molecules. That selectivity is what changes the economics of re-enriching depleted tails, material that conventional centrifuges, which separate by mass rather than by spectral signature, are poorly suited to touch. Today's light-water reactors run on low-enriched uranium at about 5% U-235, lifted from natural uranium's roughly 0.7%. Many advanced reactor designs, including several small modular reactors, will need higher-assay fuel, with U-235 concentrations up to about 20%. GLE says its process can take tails back up to a concentration equivalent to freshly mined uranium, ready for re-enrichment into reactor fuel at whatever assay a buyer wants. The NRC's laser enrichment page and World Nuclear News' technology overview describe the regulatory and physics background.

The site is what makes the project concrete. Paducah was a Department of Energy gaseous-diffusion plant that closed in 2013. The tails it left behind amount to the largest documented depleted uranium stockpile in the United States. GLE, owned by GE Hitachi and the Australian miner Silex Systems, has filed an application with the Nuclear Regulatory Commission to license the Paducah Laser Enrichment Facility. The NRC published a Federal Register notice of receipt on March 6, 2026, and the company confirmed the application was accepted for review. The company has previously said the facility, if approved, could produce several million separative work units per year. That figure is a corporate target until it is cross-checked against the license application and the NRC's environmental review.

The most credible counterargument is the cost history. Silex Systems, the original developer of the laser isotope separation process, has spent roughly two decades moving the technology from a 1990s research concept toward a commercial plant. GE Hitachi first licensed Silex's process in 2006, and the project has cycled through demonstrations, ownership changes, and a long stretch during which the economics did not pencil against centrifuge-based enrichment. The NRC review itself is likely to take years. Until the license is issued and a commercial plant is built, the Paducah stockpile is an asset revaluation on paper, not on a P&L.

The demand side is the other half of the story. The U.S. Department of Energy's existing program to make high-assay, low-enriched uranium (HALEU) available to advanced reactor developers has been slow and undersupplied, with most commercial HALEU today coming from Russian downblending. If GLE can re-enrich Paducah tails into higher-assay fuel at a price that beats centrifuge-based supply, the project would convert a regulatory headache into a strategic asset: a domestic, non-Russian source of fuel for the advanced reactor pipeline. If the demand is not there at the price GLE needs, the cylinders stay where they are, and the next-generation reactor buildout looks for fuel somewhere else.

What to watch: the NRC's review milestones and any draft environmental impact statement; GLE's throughput and SWU claims, cross-checked against the license application rather than the company release; and signed offtake commitments from advanced reactor developers for higher-assay fuel at a price that justifies the re-enrichment cost.