HALEU or LEU+? The lead test assemblies will use four test rods enriched up to 6 weight percent uranium-235, 1 percent higher than the Nuclear Regulatory Commission’s license limit. Uranium enriched to 6 percent falls within the 5 to 19.75 percent range for high-assay low-enriched uranium (HALEU), and within the 5 to 10 percent range of LEU+. While HALEU enriched above 10 percent must be handled at an NRC-licensed Category I or Category II fuel cycle facility, uranium below 10 percent enrichment can be handled at a Category III facility.
The fuel: The fuel assemblies, developed under Westinghouse’s High Energy Fuel initiative, will contain ADOPT uranium dioxide pellets and AXIOM fuel rod cladding and chromium-coated cladding, combined with the company’s PRIME fuel assembly design. ADOPT pellets and chromium-coated cladding are both part of Westinghouse’s EnCore Accident Tolerant Fuel program and were designed with support from the Department of Energy to increase fuel durability and temperature tolerance.
According to Westinghouse, the company’s High Energy Fuel initiative “enables utilities to utilize higher enrichment levels, allowing higher fuel burnup and an increase in extracted energy. Additionally, the initiative enables fuel cycles from 18 to 24 months, allowing operators to realize cost savings from reduced planned outages.”
Pam Cowan, Westinghouse president of Americas Operating Plant Services, said, “Westinghouse solutions are designed with our utility partners in mind—providing safety and economic enhancements for extended operation.”
Not Southern’s first rodeo: Westinghouse, GE Hitachi Global Nuclear Fuel, and Framatome are all working on new cladding and fuel designs through the DOE's Accident Tolerant Fuel Program, and Southern Nuclear has worked with all three vendors.
Southern Nuclear was the first utility in the world to install fuel with GE Hitachi’s accident tolerant fuel cladding, and that fuel, installed in the Hatch plant in 2018, has since been shipped to Oak Ridge National Laboratory for testing. Vogtle-2 currently holds four lead test fuel assemblies—containing full-length fuel rods developed by Framatome—that were installed in 2019.
“Our top priority is the safety and health of the public and our employees, and this game-changing technology bolsters plant reliability, strengthening our ability to support our communities and customers with the power they need around the clock,” said Southern Nuclear executive vice president and chief nuclear officer Pete Sena in a news release issued on January 27. “The installation of test assemblies with enrichments that are above historical limits marks another significant advancement in the potential commercial deployment of advanced nuclear fuel technology, which will support our ability to deliver clean, safe, reliable, carbon-free electricity for decades to come.”
DOE celebrates a “nuclear milestone”: According to the DOE, all three vendors are on track for their accident tolerant fuels to be ready for batch loading by the mid-2020s and commercially available for widespread adoption by 2030.
“Southern Nuclear and Westinghouse have been tremendous partners to our Accident Tolerant Fuel Program,” said Frank Goldner, a nuclear engineer in the DOE’s Office of Nuclear Energy. “Testing this higher-enriched fuel is a major step in deploying new fuel technologies that can help improve the economics of our existing fleet of reactors.”
