The Tennessee Valley Authority Watts Bar 2 nuclear unit has hit what could prove to be a speed bump on its way to full commercial operation – a switchyard fire that occurred Aug. 30.
“On August 30, 2016, at 2110 EDT, Watts Bar Nuclear Plant Unit 2 reactor tripped due to an electrical fault affecting the 2B Main Bank transformer, resulting in a fire in the transformer,” according to an event report filed with the Nuclear Regulatory Commission (NRC).
A TVA spokesperson on Aug. 31 stressed that the fire, which was extinguished within 90 minutes largely by the on-site fire brigade, happened at the switchyard and did not affect any reactor components.
Nevertheless, the oil fire did force the unit offline not long after it had achieved 99 percent power output. The TVA spokesperson said the federal utility was poised to start full-power testing of the nuclear unit that was synched to the grid in June.
It’s “too early to say” if the switchyard fire will significantly affect the schedule for full commercial operation, the spokesperson said. “We are currently assessing the site there” to determine both the extent of damage and the cause of the fire, the spokesperson said.
Earlier this year, TVA President and CEO Bill Johnson said that “commercial” operation is a largely an accounting term for when a reactor runs at 100 percent power, or close to it, for about 20 days.
The fire had no impact on the operation of Watts Bar 1, according to the NRC report.
"The fire was out at 2230 EDT. The cause of the fire is currently under investigation. …The fire was reported at 2149 EDT. Local Fire Departments responded to the site as requested,” according to the event report filed with NRC.
The new reactor is designed to add 1,150 MW of electricity generating capacity to southeastern Tennessee.
The commercialization of the TVA Watts Bar 2 facility – which sat unfinished for more than 20 years before the TVA board voted to complete the project in 2007 – has been a rare bit of good news for the nuclear industry this year.