The lead fuel assembly (LFA) is running in Unit 2 of the Calvert Cliffs plant in Maryland.
The first complete assembly of enhanced accident-tolerant fuel (E-ATF) to operate in a commercial nuclear reactor has successfully completed its second 24-month operational cycle and has been loaded for a third cycle.
The lead fuel assembly (LFA) is operating in Unit 2 of Constellation’s Calvert Cliffs plant in Maryland. It recently underwent testing and inspection during the 2025 spring refueling outage after completing its second two-year cycle in the pressurized water reactor (PWR).
“This fuel assembly will continue operating under commercial conditions, providing crucial data to support the nation’s energy objectives,” said Frank Goldner, the federal program manager for the Accident Tolerant Fuel Program.
The LFA was first loaded in 2021. It completed its first 24-month cycle and was subsequently examined and reinserted for a second cycle in 2023. Teams from the manufacturer, Framatome, and the operator, Constellation, have conducted inspections after each cycle.
“The lead fuel assembly is the first of its kind to operate in a commercial reactor,” highlighted the DOE in a press release.
The assembly is now scheduled to complete its third 24-month cycle in the spring of 2027. Following this, it will be shipped to a US Department of Energy (DOE) national laboratory for detailed post-irradiation examination to help inform future licensing activities.
Accident-tolerant fuel (ATF) is a term for new technologies designed to enhance the tolerance of light-water reactor fuel under severe accident conditions.
It also aims to enhance reactor performance and economics by incorporating new materials and designs for fuel pellets and cladding.
This specific assembly contains 176 chromium-coated rods and chromia-enhanced pellets.
The DOE, which supports Framatome’s PROtect E-ATF programme, stated these materials can better respond to changes in the reactor core and are expected to reduce corrosion and hydrogen production during high-temperature conditions.
“The performance of our technology continues to demonstrate the expertise of our people to develop safe, cost-effective solutions for our customers and our industry,” said Lionel Gaiffe, senior executive vice president of the Fuel Business Unit at Framatome.
Industry adoption and wide impact
The fuel was fabricated at Framatome’s manufacturing facility in Richland, Washington, as part of a contract with Constellation in 2019. Framatome noted that chromia-enhanced pellets are now a standard feature in its ATRIUM 11 boiling water reactor fuel design, which is operating in eight other US commercial power plants.
According to the DOE, the fuel prototype builds on previous testing in the USA and Switzerland and could deliver the industry’s first major upgrade to nuclear fuel technology since the 1970s.
“The new fuel and cladding mixtures could help improve the overall economics and performance of today’s reactors,” concluded the press release.
Framatome, GE Vernova, and Westinghouse are currently testing various fuel concepts in commercial reactors across the US, with the goal of achieving widespread adoption by 2030.
Source: Interesting Engineering
