Browns Ferry Nuclear Plant has been selected by S&P Global Platts as a finalist for the Global Energy Award — Construction Project of the Year — for the successful completion this year of the Extended Power Uprate (EPU) project, according to a press release from the Tennessee Valley Authority.
The $475 million EPU project was a five-year project that allows the plant to safely produce an additional 465 megawatts of carbon-free energy, which is enough electricity to power 280,000 homes. Browns Ferry is the nation’s second largest power plant and is operated by TVA.
Winners will be announced at the Global Energy Awards gala on Dec. 12 in New York City.
“As the nation’s largest public power utility, we share this recognition with everyone who benefits from Brown Ferry’s clean, low-cost electricity,” said Steve Bono, Browns Ferry site vice president. “Being selected as a finalist demonstrates TVA’s leadership, innovation and commitment to safety in the nuclear industry.”
Browns Ferry is the first three-unit site to implement EPUs. The EPUs also solidify Browns Ferry’s position as TVA's leading power producer with up to 3,933 megawatts in total power across all three units. Of the nearly 60 percent carbon-free energy TVA produces, more than 40 percent of that electricity comes from nuclear power.
In order to increase the plant’s electricity output, a dedicated project team worked for nearly two years to conduct a rigorous engineering analysis and develop more than 200 plant modifications. Before work could begin, the team presented plans to and gained approval from the Nuclear Regulatory Commission.
The EPU project itself was supported by more than 50 vendors from 20 states. Final EPU modifications were made during each unit’s recent refueling outage, starting in spring 2018 and running through summer 2019. During a typical refueling outage, approximately 300 additional personnel are added to the plant workforce. EPU outages require more than 150 extra personnel to support the additional work required for the uprate.
“This was a team effort all the way and demonstrates how TVA builds effective partnerships to meet the current and future energy needs of the Tennessee Valley,” said Pete Donahue, EPU project lead.
EPU modifications included higher capacity pumps as well as replacement steam dryers and refurbished high-pressure turbine rotors. One of the industry issues with power uprate has been damage to the steam dryers as a result of higher steam flow. To overcome this problem, Browns Ferry replaced the steam dryers with a much more robust design capable of withstanding the higher steam flows.
In addition, TVA invested in training, control-room simulator scenarios and procedure revisions to prepare licensed operators and other employees for safe and reliable plant operations at the higher EPU power level. TVA's EPU project team conducted extensive power ascension testing on each unit to ensure safety and verify plant response before going to full EPU power.
Bill Baker, senior manager of EPU operations, noted the importance of getting operators involved early on.
“We benefited from industry learnings, as many plants have previously completed this work. We learned to engage operators early and often. We began to introduce changes and simulation tests two years before implementation. This helped operators identify challenges up front and be confident about the operation of the plant,” Baker said. “This also helped us identify better processes that we are sharing across the industry.”
Baker said everyone across the plant came together to make the EPU a success, not only operators.
“Our employees are experts, and engaging them in the process built confidence across each work group in the changing conditions,” he said.
By listening to employees, Baker said various design changes were developed to improve safety margins, often margins greater than existed prior to EPU.
Innovative heavy lift
As part of the extended power uprate, Browns Ferry used an innovative method to move massive plant components using remote-controlled crawlers. This resulted in industry recognition with a 2019 Top Innovative Practice Award from the Nuclear Energy Institute in June.
A team of TVA and Barnhart Crane & Rigging employees combined two remote-controlled, low-profile crawler vehicles to transport 35.5 tons of feed water heater tube bundles, which measured 46 feet in length and 7 feet in diameter — roughly the size of a school bus but twice the weight.
“These tube bundles are long and heavy,” said Ashley Michael, Browns Ferry EPU implementation lead. “The typical fix for moving these kinds of components includes tracks or rails, but that would have required reinforcing the floor, which would have added extra time, labor and materials to the outage.
“Instead, we put together two remote-controlled crawlers that could operate independently to navigate through the 90-degree turns from the inside of the turbine building, through the service building, and positioned outside to be lifted by a crane.”
This is the first time that a double skid-steer configuration has ever been used to remove and replace plant components of this magnitude.
“By using this method, we reduced the outage schedule by seven days. Once implemented, we finished seven days early, which is a significant cost and schedule savings for the project,” Michael said.