The Tennessee Valley Authority’s Browns Ferry Nuclear Plant Unit 2 started a scheduled refueling and maintenance outage this past weekend after generating more than 19 billion kilowatt-hours of carbon-free electricity in 654 days of reliable operation. This outage includes the largest scope of turbine deck work since original construction and innovations in fuel assembly components.
All three of the unit’s low-pressure turbines will undergo a comprehensive replacement of major components, including new rotors, inner casings, steam piping and bellows and turbine supervisory instruments. These tasks will require the support of more than 500 additional outage workers and an incredible amount of heavy lifting – with 600 separate crane lifts of components such as rotors weighing up to 327,888 pounds and inner casings weighing up to 200,000 pounds.
Once the Unit 2 turbine project is complete, the unit will generate an estimated 7 megawatts of additional electricity, enough to power more than 4,000 additional homes.
“TVA’s investment in Browns Ferry and the infrastructure of our power systems ensures that we can continue to provide reliable power for our local power companies and communities when they need us most,” said Browns Ferry Site Vice President Matt Rasmussen.
With these upgrades, Unit 2 will essentially have three brand-new low-pressure turbines, which help convert steam into electricity, increasing the safety and reliability of power generation well into the future. This helps support TVA’s mission of service and economic development, ensuring the energy needs of the Tennessee Valley are met, particularly during the peak demand periods of summer and winter.
While major upgrades are happening on the turbine deck, the refueling team will load four new 3D-printed fuel assembly brackets in the reactor. The brackets demonstrate the latest innovations in additive manufacturing and artificial intelligence. They will be the first of their kind loaded into a commercial reactor. The components were recently manufactured at Oak Ridge National Laboratory in a joint project with TVA and the utility’s fuel supplier, Framatome, as part of the lab’s Transformational Challenge Reactor program.
“Being the first to use these additively manufactured components supports an innovative manufacturing approach that could pave the path for use across the existing nuclear fleet and in advanced reactors and small modular reactors,” said Dan Stout, TVA’s director of Nuclear Technology Innovation.
In total, the Unit 2 outage will feature more than 14,800 scheduled work activities, including the installation of 320 new fuel assemblies along with upgrades, modifications, repairs and testing of other plant equipment, inspections of reactor components and maintenance of key safety systems. To safely complete this outage, TVA has augmented the Browns Ferry workforce with an estimated 1,300 additional employees, including those being brought in for the turbine upgrade project.
Browns Ferry Unit 2 is one of seven operational TVA nuclear reactors across the Valley.
"Collectively, TVA’s nuclear fleet is the third largest in the nation, safely and reliably providing more than 40 percent of all electricity used by nearly 10 million people in the Tennessee Valley," officials said.