Ten weeks after a magnitude 5.8 earthquake knocked a central Virginia nuclear power station offline, the plant’s operator, Dominion Virginia Power, is still waiting for the go-ahead from the Nuclear Regulatory Commission to restart the North Anna power plant’s two reactors.
“We want to make absolutely certain that there is nothing we haven’t evaluated yet,” said Roger Hannah, an NRC spokesman.
At a public meeting in Mineral, Va., on Tuesday night, an NRC inspector said a decision to restart the reactors could come as early as next week.
“Reviews are in progress. However, the staff has not identified any significant safety concerns resulting” from the earthquake, said Meena Khanna, the NRC’s lead inspector at the facility.
Gerald McCoy, the NRC official overseeing the inspection team, said the NRC directed the company to perform inspections on an underground steam tunnel and on support struts holding up one of the nuclear reactor pressure vessels. The company had not adequately inspected those areas, McCoy said, but the NRC team found no significant problems.
On Oct. 21, Dominion told the NRC it thought both reactors were safe to restart. The company said it spent more than 100,000 man-hours on inspections, testing and minor repairs, at a total cost of $21 million.
Dominion fixed small cracks in office buildings and replaced part of an electrical transformer that leaked oil after the quake, said Dominion spokesman Richard Zuercher.
The company sent small robots into the pool that holds nuclear fuel in the Unit 2 reactor and found no damage to the containment structure or the nuclear fuel, Zuercher said. The company had opened the reactor to refuel it.
The NRC told the company it did not need to perform similar inspections inside the Unit 1 reactor, Zuercher said.
The most powerful quake to rattle Virginia in more than a century shook the power plant more than it was designed for in one horizontal direction for 1.5 seconds during the 25-second quake. But extra safety margins in the plant’s structure prevented more than minor damage, Zuercher said.
When operating, North Anna provides 17 percent of Virginia’s electricity.
Zuercher said the company had not decided whether to seek an increase in the rates customers pay to cover the costs of the outage.
North Anna is the first nuclear power plant to shut down after an earthquake in the 53-year history of commercial nuclear power in the United States.