Operators at the Tennessee Valley Authority (TVA) Watts Bar 2 facility declared a Notice of Unusual Event — the least severe of the four Nuclear Regulatory Commission (NRC) emergency classifications — at 3:42 a.m. EST on Wednesday, March 9, after a small fire occurred in one of Unit 2’s hotwell pump motors.
TVA reported that plant personnel extinguished the motor fire and there was no danger to the public. The unusual event notice was exited at 5:08 a.m. after operators confirmed that all plant systems were operating as designed.
An event report filed with NRC indicated that no off-site fire squad was requested for putting out the small fire. The event report noted that the fire was extinguished by 4:01 a.m., or less than 20 minutes after it was reported.
Other Watts Bar Unit 2 systems were unaffected. Watts Bar Unit 1 was also unaffected and remained safely online throughout the event, a TVA spokesperson said.
The NRC and other appropriate officials have been notified and an evaluation of the motor failure will be conducted.
Hotwell pumps are part of the unit’s condenser system and help recirculate water condensed from steam after it passes through the turbines used to generate electricity. They are located on the power generation side of the plant and are not directly associated with the reactor or reactor cooling system.
There were no impacts to the numerous nuclear safety systems in the plant, TVA said.
“The evacuation of the pump is still underway but the fire damage was limited to that one component,” said the TVA spokesperson. “Obviously, repairs will be necessary but the fact that none of the surrounding systems appear damaged less us to believe this will not have a significant impact on the startup schedule.”
Meanwhile, TVA continues to work on starting commercial operation of the second 1,150-MW pressurized water reactor (PWR), the TVA representative added.
“Currently, we are continuing the pre-operational checks that will lead to the initial reactor criticality within the next few weeks. After that, we’ll move through a series of power ascension tests,” the spokesperson said.
In October, TVA received its long-sought NRC operating license for Watts Bar 2. NRC has approved the process for TVA to begin putting the nation’s first new nuclear generation of the 21st century into service at the site near Spring City, Tenn.
TVA has also loaded fuel into the reactor in anticipation of start-up operations.