Nuclear

Watts Bar Unit 1 adds additional 24 MW after refueling and maintenance outage

The team attributes the increase for Unit 1 to upgrades made during the planned outage, such as replacing two low-pressure turbine rotors and increasing the cooling tower, condenser and plant efficiency.
Watts Bar Unit 1 adds additional 24 MW after refueling and maintenance outage
The Tennessee Valley Authority’s Watts Bar Nuclear Plant (Credit: TVA).

The Tennessee Valley Authority’s (TVA) Watts Bar Nuclear Plant Unit 1 returned to operation last week after the team completing a scheduled refueling and maintenance outage that will add approximately 24 megawatts (MW) of electricity to the unit’s typical 1,200 MW output.

During the outage, the Watts Bar team completed more than 12,000 work activities to return the unit to full generating capacity and supply enough energy for at least 650,000 homes.

“The work our team members completed during this outage will allow us to continue to provide safe, reliable, carbon-free electricity for people throughout the Tennessee Valley for the next 18-month operating cycle,” said Chris Reneau, Watts Bar site vice president. “As the region continues to grow at a rapid rate and the need for power grows with it, we’re appreciative that our highly skilled team of TVA, union, and contract partners works safely and with full attention to craftsmanship and operational excellence to make the upgrades and enhancements further to improve the reliability of Unit 1 and our plant.”

Inspections, upgrades, and updates

In addition to replacing 92 of Unit 1’s 193 fuel assemblies, the Watts Bar team performed inspections of reactor components and other plant systems in an effort to ensure continued safe operation of components, replaced or serviced plant equipment and installed enhancements. The team attributes the increase in power for Unit 1 to upgrades made during the outage, such as replacing two low-pressure turbine rotors and increasing the cooling tower, condenser, and plant efficiency.

Watts Bar is TVA’s second largest nuclear plant—its two pressurized water reactors produce about five percent of TVA’s total generation capacity. Each unit produces about 1,150 MW of electricity. Watts Bar Unit 1 is one of seven operational TVA nuclear reactors across the Valley, with TVA’s nuclear fleet providing more than 40% of all its electricity generated.

Over the summer, TVA named new leadership for the Watts Bar nuclear plant. Chris Reneau was named site vice president, effective June 12. Current Watts Bar Site Vice President Tony Williams stepped into the role of Vice President, Outage Services and Supplemental Resources for TVA’s entire nuclear fleet. Reneau most recently served as vice president for operations support at the TVA Nuclear Fleet Center in Chattanooga. Since joining TVA in 2009, he has held multiple leadership roles, including Senior Manager Systems Engineering, Senior Manager Design Engineering, Site Engineering Director and Director of Operations before becoming Plant Manager at the Sequoyah Nuclear Plant in 2021.

Unit 1 at Watts Bar entered commercial operations in 1996. In 1988, TVA suspended construction activities on Unit 2 due to a reduction in the predicted power demand growth. In 2007, TVA approved the completion of Unit 2 after finishing studies of energy needs, schedule, costs, environmental impacts and financial risks.

In November 2022, TVA’s Watts Bar Unit 2 completed a steam generator replacement project at the 1,150 MW facility in eastern Tennessee. Unit 2 entered service in 2016 at a construction cost of $4.7 billion.

The original steam generators were built in the 1970s using a metal alloy that prematurely developed leaks and other problems at other nuclear plants. The equipment was installed at Watts Bar in the 1980s before TVA halted work at the site due to cost overruns, employee safety concerns and a drop in projected power demand. 

TVA determined it would be too costly to replace the original steam generators when construction resumed, so Unit 2 entered service with its original steam generators. The cost to replace the steam generators rose to around $590 million and took weeks longer to install than originally expected due to weather issues.