A Dallas startup says it made advanced-reactor fuel with a calutron

Why it matters

Actinide's lab result does not create a commercial HALEU supply, but its direct-to-solid process could remove a costly step from a fuel chain holding back advanced reactors.

A year-old Dallas startup says it has done something the United States badly needs more of: turned natural uranium into advanced-reactor-grade fuel.

Actinide said Tuesday that a Texas-built electromagnetic isotope separator enriched a laboratory batch of uranium to 15.38% uranium-235, inside the range known as high-assay low-enriched uranium, or HALEU. An ISO/IEC 17025-accredited laboratory independently measured the sample, according to the company. The Nuclear Regulatory Commission defines HALEU as uranium containing between 5% and 20% uranium-235. Actinide describes the test as the first time a startup has enriched natural uranium into HALEU, a claim that has not been independently established. (actinideinc.com)

The machine is a calutron: a hulking electromagnetic separator descended from the technology used at Oak Ridge during the Manhattan Project. Actinide's version, called Endurance, had been separating rare ytterbium isotopes for Oklo Isotopes weeks earlier. The company reconfigured it for uranium and says it produced HALEU directly as a solid material.

That last point is the bet. America can enrich uranium in centrifuges, but centrifuges output uranium hexafluoride gas. Before advanced-reactor developers can use it, that gas needs to be converted back into a fuel-ready solid - a commercial HALEU deconversion industry the country does not yet have.

Actinide has only shown a research-scale batch under a laboratory-scale exclusion in federal regulations. It has not created a commercial fuel supplier, and the recovered material would still require fabrication into a usable fuel form such as pellets, rods or particles. But if its process survives the far harder tests of throughput, cost, safeguards and NRC licensing, the company could collapse two hard industrial steps into one machine. (ecfr.gov)

They built a Manhattan Project machine in Texas

Eric Olszewski and Robert Mendelsohn founded Actinide in September 2025 after Mendelsohn spent seven years researching and prototyping the separation technology, according to Actinide's announcement. Olszewski said he began financing the work before Actinide was incorporated, moved his family to Dallas in early 2024 to work alongside Mendelsohn and put more than $1 million of his own money into the project.

Actinide says its March 2026 seed round was led by Onto Ventures, with participation from Neo Ventures, Mana Ventures, Discipulus Ventures, Shor Capital and angel investors including Ryan Hiepler and Stephen Cole.

Endurance sends charged atoms through a magnetic field to separate isotopes, applying the same underlying electromagnetic principle as the calutrons built during the Manhattan Project. Actinide is positioning the machine as a general-purpose manufacturing system that can be reconfigured for isotopes used in nuclear energy, medicine, quantum systems and electronics.

That flexibility is central to Mendelsohn and Olszewski's bet: a smaller private operator can sell scarce materials while building toward the scale and regulatory approvals required for nuclear fuel. Mendelsohn said Actinide's machines cost a few hundred thousand dollars and can be reconfigured within days. Those figures are Actinide's estimates, and their commercial relevance will depend on whether the machines retain acceptable throughput, purity and operating economics as production scales.

The missing link in the HALEU supply chain

Many advanced-reactor developers plan to use HALEU because its higher concentration of uranium-235 can support smaller reactor cores, longer operating cycles and more efficient fuel use. The Department of Energy says HALEU remains unavailable from domestic suppliers at the scale required for commercial deployment.

Centrus Energy has already produced HALEU in Ohio through a federally backed gas-centrifuge demonstration, including an initial 20-kilogram delivery to the government in 2023. The NRC also lists Louisiana Energy Services as licensed to produce uranium enriched to 5.5%. Actinide's distinction rests on its startup status, laboratory-scale regulatory basis and electromagnetic process, rather than being the first American organization to produce HALEU. (nrc.gov)

The electromagnetic process could address a separate bottleneck. The United States lacks commercial-scale HALEU deconversion capacity, and the Energy Department awarded six companies contracts in 2024 to compete for work building that capability. Actinide says producing solid HALEU directly would bypass that step. (energy.gov)

That advantage currently exists only at research scale. Commercial uranium enrichment carries extensive licensing, safeguards, security and material-accounting requirements. Actinide will need to move from a laboratory exclusion to a regulated production operation before its HALEU can enter a commercial reactor supply chain.

The founders are already building Fortitude, a second-generation separator. Based on Actinide's engineering estimates, one Fortitude machine would deliver about half the isotope-separation capacity of the federal government's current electromagnetic fleet. The estimate has not been independently tested, and it measures separation capacity rather than reactor-fuel output.

The timing gives Actinide a receptive buyer market if the technology scales. U.S. civilian nuclear operators bought 77% of their enrichment services from foreign sources in 2025, including 26% from Russia, according to the Energy Information Administration. The federal government has since committed billions of dollars to expanding domestic enrichment and deconversion, including $900 million task orders awarded in January 2026 to Centrus subsidiary American Centrifuge Operating and General Matter.

Actinide has not solved America's HALEU shortage. It has shown, with a small batch and a lab result, that a different route may exist: skip the gas, skip the missing conversion plant, and make the enriched material in solid form from the start.

For a country trying to restart an advanced-reactor fuel supply chain, that is a much bigger claim than "a startup enriched uranium."