US unit cleared to use higher-enriched fuel

03 October 2023

Southern Nuclear has announced it has received authorisation from the US Nuclear Regulatory Commission (NRC) to use advanced nuclear fuel enriched up to 6% uranium-235 at Vogtle unit 2. This is the first time a US commercial reactor has been authorised to use fuel with over 5% enrichment.

(Image: Southern Nuclear)

The regulatory authorisation means that manufacture of four first-of-a-kind lead test assemblies (LTA) of the next-generation so-called Accident Tolerant Fuel (ATF) that will use key components from Westinghouse's High Energy Fuel initiative and the EnCore Fuel programme can now begin, Southern Nuclear said. It envisages loading the fuel into the reactor in 2025.

Southern Nuclear signed an agreement with Westinghouse in 2022 to load the four LTAs at Vogtle. The assemblies will feature Westinghouse's trademarked ADOPT uranium dioxide pellets, AXIOM fuel rod cladding and chromium-coated cladding combined with its advanced PRIME fuel assembly design.

ATF is a "game-changing" technology that will advance performance and further strengthen grid reliability, said Southern Nuclear President Pete Sena, who also recognised the regulator for its "thorough yet timely review of this installation to support the future of commercial nuclear power in our country."

Tarik Choho, Westinghouse's President of Nuclear Fuel, said support from members of the US Congress and the Department of Energy (DOE) had been "critical" to the company's ability to advance fuel technology with higher burnup rates. "We are grateful to Southern Nuclear for their trust and look forward to delivering advanced technologies that will bolster the light water fleet and support the low-cost generation of nuclear power in the long term," he added.

ATFs enhance the tolerance of light-water reactor fuel under severe accident conditions, but also offer improvements to reactor performance and economics during normal operations as well as in transient conditions and accident scenarios. Fuel with higher enrichment lasts longer, extending the time between refuelling outages, as well as potentially reducing fuel costs as less fuel assemblies are needed.

But the current existing US licensing approach means it takes a long time to obtain regulatory approval for such fuels. Southern Nuclear - which operates a total of seven units for Alabama Power and Georgia Power including the four units at Vogtle - said it is working alongside the DOE, fuel suppliers and other utilities in a "coordinated, overarching, multi-year effort" in the US Nuclear Energy Institute's ATF Working Group to "expand the regulatory paradigm".

Southern Nuclear installed GE-Hitachi ATF fuel cladding technologies in 2018 at Hatch unit 1 in another ATF "first", with samples subsequently discharged and shipped to Oak Ridge National Laboratory for further testing in 2020. In 2019, it installed four Framatome-developed GAIA lead fuel assemblies - containing enhanced accident-tolerant features applied to full-length fuel rods - in Vogtle 2.

Southern Nuclear said it received the NRC approval on 1 August.

Researched and written by World Nuclear News