Dominion Virginia Power said Friday it won’t restart the two nuclear reactors at its North Anna Power Station rattled by the Aug. 23 earthquake until the company is convinced it is safe.
The plant about 11 miles from the central Virginia epicenter of the 5.8-magnitude quake was shut down within seconds of the tremor that shook tens of millions along the East Coast. Officials at the Richmond-based company said the damage was only cosmetic and the plant is safe. Damage ranged from small buckles and cracks in tile floors in one of its technical buildings, to bolts of large metal parts that transfer power from transformers to the electrical grid and into homes.
Dominion also said the earthquake caused 25 massive nuclear storage containers at the plant to shift, but they remained intact. The containers are used to store used fuel and weigh about 115 tons when full. The company is evaluating whether to move the containers back, but said they are still safely spaced.
“The plant is safe, we have seen no significant damage from any of our inspections thus far, there was no release of radioactivity,” said Dan Stoddard, senior vice president of nuclear operations for Dominion.
Officials are still reviewing what happened at the facility after the quake, and inspections continue. Stoddard said the final analysis is expected to be completed by the end of next week, but he could not say when the reactors will be restarted. The Nuclear Regulatory Commission also is inspecting the plant.
Based on preliminary data, the plant did exceed some seismic measures for its site design but was still within safety margins, Stoddard said.
The information officials gather will help determine what safety improvements are needed. The plant had been previously upgraded to improve its ability to withstand seismic activity under a nationally mandated safety evaluation.
“What we want to do is learn from it and harden our facility and correct any deficiencies. Right now we see no deficiencies,” said Larry Lane, site manager for the facility that sits on a 1,200-acre area near Lake Anna, a popular recreational location built by Dominion to work with the cooling water at the plant.
Within seconds of the afternoon tremor, the plant automatically shut down. At that time, the facility lost off-site power and control rods dropped into the reactor core and stopped the nuclear chain reaction, shutting down the reactor. Officials are unsure whether the rods fell due to the shaking or loss of power, but the rods dropping is not unusual and can happen even during something as simple as a blown fuse.
When the quake hit, unit supervisor Jason Russell, 30, was standing behind the counter of the control room, a vast space filled with walls of colored and lighted buttons to help engineers monitor all of the facility’s parts. Russell immediately informed his team to enter emergency procedures, but the system had already automatically shut down for safety.
“We felt the shaking and we weren’t necessarily sure it was an earthquake. It didn’t correlate, but we knew we had something going on,” said Russell, who like others in the control room has practiced emergency scenarios like an earthquake during training. “It was definitely exciting initially, but then you kind of just go back to what you’re trained to do.”
The two North Anna reactors are among 27 in the eastern and central U.S. that may need upgrades because those plants are more likely to get hit with an earthquake larger than the one on which their design was based, according to a preliminary Nuclear Regulatory Commission review.
“As with any event that happens, whether it’s naturally driven or equipment failure, we always analyze the event in depth as we are doing now to understand it, to learn from it and improve safety,” Stoddard said. “We will take advantage of this as a power plant, as a company and as an industry to learn and improve.”
When fully operational, the plant produces enough energy to power about 450,000 homes. Dominion is using other power sources in its generation system to make up for the plant being offline. The cost of shutting down the plant was not available.
The company is still weighing the addition of a third reactor at the Louisa County power plant, but has not yet committed to move forward with the project and will reassess when it receives operating approval from the NRC expected in 2013.
Dominion Virginia Power is a subsidiary of Dominion Resources Inc., one of the nation’s largest producers and transporters of energy and has the nation’s largest natural gas storage system. It serves retail customers in 15 states.
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