US Tennessee Valley Authority (TVA) said unit 2 of its Browns Ferry NPP in Alabama had resumed operation on 22 April, following the completion of a scheduled maintenance and refuelling outage. This included the largest scope of turbine deck work since original construction, with large-scale replacements of major components on all three low-pressure turbines, including new rotors, inner casings, steam piping and bellows and turbine supervisory instruments. This will enable the unit to generate an additional 7MWe. 

“This investment by TVA helps ensure Browns Ferry continues to provide safe, reliable, clean energy to our local power companies as we enter the region’s summer peak season and beyond,” said Browns Ferry Site Vice President Matt Rasmussen. More than 18,000 work activities were completed, including major repairs to reactor components and the installation of 320 new fuel assemblies along with upgrades, modifications, repairs and testing of other plant equipment and routine maintenance of key safety systems.

The refuelling team also loaded four first-of-a-kind, 3D-printed fuel assembly brackets into the reactor. The brackets were manufactured at Oak Ridge National Laboratory in a joint project with TVA and Framatome as part of the lab’s Transformational Challenge Reactor programme. The brackets will remain in the reactor for six years with inspections planned during outages and after use. Browns Ferry 2 is one of seven operational TVA nuclear reactors across the Valley.

The plant comprises three General Electric boiling water reactors with Mark I containment. Browns Ferry 1 entered commercial operation in December 1973, followed by unit 2 in June 1974 and unit 3 in July 1976. All three units have been granted 20-year operating licence extensions by the US Nuclear Regulatory Commission allowing them to remain in service until the 2030s.

More than 500 additional TVA contractors and employees worked over seven weeks to complete the upgrade. It comes just two years after TVA completed a four-year, $475 million power upgrade at all three of Browns Ferry reactors which collectively added 465MWe. Browns Ferry now has a total generating capacity of more than 3.4GWe gigawatts, the second biggest US NPP exceeded only by the Palo Verde NPP in Arizona.