Next Gen Uranium-235 Fuel System in Use at Georgia’s Vogtle Plant Has Higher Enrichment and Better Heat Resistance

     The first reactor of Southern Company’s Vogtle nuclear power plant in Georgia came online in 2023. It was the first new reactor built from scratch to come online in the U.S. for three decades, although it was years behind schedule and billions above original cost estimates. Last year, the second reactor at Vogtle came online. In April of 2025, that reactor became the first in the U.S. To be powered by second-generation nuclear fuel, uranium-235 that is enriched above 5%. This also enables the reactor to last longer between refueling times and generate less radioactive waste. The article in Fortune notes that it is not yet clear whether other older reactors will be outfitted to run on the higher-enriched fuel. Cost and age of the reactors are factors.

     The fuel is in the form of pellets that can easily be dispensed into the reactor. It has been analogized to a Pez dispenser. The pellets are “doped” with materials such as chromium oxide and alumina to improve performance under high temperatures. The dispenser cladding is doped with zirconium for the same reason. These coatings mean that in case of an accident, there would be much more time to cool the reactor core, if needed. The higher-enriched fuel means that refueling intervals of 18 months can be extended to 24 months.

    Fortune attempted to ascertain whether other companies were interested in buying the fuel, but apparently, none were, at least not yet, as the zirconium-coated cladding has yet to be commercialized, and that could take a decade. Dominion Energy did say that they were considering it for the future. Constellation said they would consider it when commercialized. Ken Peterson, former president of the American Nuclear Society, noted:

“New nuclear plants won’t come online anytime soon, so maximizing existing facilities is critical. “If you look at U.S. capacity factors, we’re higher than anybody else. We’re pushing up against those limits, and that’s why we need this additional enrichment.”

     A 2019 whitepaper by the Nuclear Energy Institute notes that demand for higher-enriched fuel will grow, as there is increased interest in higher burnup reactor cores. Higher enrichment enables higher burnup.

“With the increased interest in higher burnup cores, it is likely that within the next decade, both operating and advanced reactors will see a demand for fuel enriched greater than 5 weight percent (wt%) U‐235.”

     They also explain that the degree of enrichment and level of burnup make up nearly all of the possibilities to decrease fuel costs, aside from the raw uranium commodity costs.

“A site’s fuel costs depend on two factors, the price of the fuel components (uranium feed, conversion, enrichment, and fabrication) and the efficiency of the core design. Fuel component costs are driven by supply and demand and are largely outside the control of a utility. The efficiency of a core design determines the quantity of nuclear material needed to meet a plant’s energy objectives. While a utility can improve the efficiency of the core design, this efficiency is ultimately limited by the specific design constraints of the core design. Two of several constraints that have been shown to directly impact the core design efficiency are the uranium enrichment level and discharge burnup achieved by the core and/or fuel design. A review of the current fuel management practices, based on equilibrium cycle designs, has shown that 99% of the variation in fuel cycle efficiency is attributable to variations in enrichment and burnup. Many sites are currently constrained by the existing regulatory limits on one or both of these parameters.”

 

    

 

References

 

Southern Co. quietly makes next-gen nuclear fuel history in Georgia. Alexander C. Kaufman. Fortune. June 12, 2025. Southern Co. quietly makes next-gen nuclear fuel history in Georgia

The Economic Benefits and Challenges with Utilizing Increased Enrichment and Fuel Burnup for Light‐Water Reactors. Nuclear Energy Institute. February 2019. NEI-White-Paper-The-Economic-Benefits-and-Challenges-with-Utilizing-Increased-Enrichment-and-Fuel-Burnup-for-LWR.pdf