An alarm rang and alert lights came on at two area nuclear power plants while many in the region awoke in their beds Dec. 12 during Tennessee's strongest earthquake in 45 years.
A Tennessee Valley Authority operator checked the warning lights that had just turned red, letting him know there had been an abnormal operating procedure. Water in refueling tanks had shifted, sparking one light. The turbine also was alerting to ground vibration, activating another. The operator ensured systems were running normally before turning to a second worker. He had pulled out a binder with scenarios: the TVA playbook for any abnormal event.
The two spoke through what had just occurred, what the machines were telling them and whether all nuclear operations were still properly working. They were. The two confirmed everything was working fine. Despite the earthquake, nothing had been damaged.
"These guys are trained to take immediate action when it warrants it," said Kevin Michael, operation superintendent at the Sequoyah Nuclear Plant near Soddy-Daisy. "Ninety-nine percent of this is going to be scripted."
Assistant operators were then sent out to verify the findings. Despite the computer readings, they wanted human verification that everything was working properly.
That was soon confirmed, and before many in the community realized they had slept through the magnitude-4.4 earthquake in Meigs County, less than 10 miles north of Decatur near Watts Bar, nuclear operators had confirmed there had been no negative impact on the facility and operations never ceased.
"There was some concern in the community," TVA spokesman Scott Fiedler said. "You have an earthquake next to a nuclear facility."
So, the federally run power company invited members of the media to its training facility. Officials wanted to demonstrate to the community what happens when an earthquake strikes. They recreated the events of that day and then created a training scenario to demonstrate the effect of an even stronger earthquake.
The nuclear facilities have long been built to withstand such incidents.
"This whole plant is designed with a seismic event in mind," Michael said.
The engineers who designed and built the facility looked at the most severe disasters dating back centuries. They tweaked designs to withstand such events and then confirmed those readings throughout the construction process. There's leeway within the design to allow for ground movement and then to report any abnormal readings. Emergency plans were put in place for each scenario, and others were added in case a never-before-seen disaster struck East Tennessee.
Operators go through training every five weeks. In all, they each get about 240 hours of training yearly. That's after they go to school for their four-year degrees and then receive two years of additional training. They have six weeks of requalification every year and retake a work exam annually.
"The burden on this job is greater than any other job that I'm aware of," Sequoyah Nuclear Plant Engineering Director Chris Remeau said.