Dominion Virginia Power on Friday began the restart of North Anna Power Station after garnering the Nuclear Regulatory Commission’s (NRC’s) permission and more than two months of inspections, testing and engineering, and seismic analysis to investigate effects of the Aug. 23 5.8-magnitude quake whose epicenter was only about 11 miles away from the company’s twin-reactor station in Mineral, Va.
On Friday, control room operators, under the oversight of both Dominion nuclear officials and NRC inspectors, initiated the restart process for Unit 1. The company first will bring Unit 1 online safely and then begin the same process with Unit 2. It is expected to take about 10 days to return both units to 100% power.
“The restart process for each unit normally takes about four days from cold shutdown to normal power operations in which electricity is produced and placed on the electric grid. During the restart process, hundreds of pumps, motors, valves and other systems are restarted in a carefully prescribed and observed sequence,” Dominion said in a statement on Friday. “Because the units will be starting up after the first earthquake to shut down a nuclear unit in the United States, the restart process will be prolonged to allow for additional equipment tests that can only be performed when the units are in various stages of start-up as an extra, deliberate safety precaution.”
Delays could occur and are not atypical even during normal startups, as operators decide that additional checks or maintenance are needed, the company said.
The NRC recently completed its inspection of the station and independently confirmed the company’s finding of no functional damage. In its Nov. 11, 2011 letter, the agency gave the company formal permission to begin the restart. As part of its restart agreement with the NRC, the company will perform a number of actions after restart to analyze and confirm North Anna’s capability to withstand seismic events now and in the future.
The company immediately began a program of inspections, testing and analysis to make sure the station was undamaged and capable of being safely restarted. “The program involved more than 100,000 man-hours of work and cost more than $21 million, plus the use of numerous outside seismic and engineering experts,” Dominion said.
Sources: POWERnews, Dominion, NRC