NRC to inspect Shearon Harris after equipment failure

The Progress Energy plant, located about 20 miles southwest of Raleigh, had shut down and was in the process of cooling down for refueling on April 21 when two main steam isolation values failed to close, NRC officials said. Following additional operator actions, one of the two valves was closed a little more than half an hour later, but the second valve took three hours to close, they said.

Main steam isolation valves play an important role in limiting the release of steam in a nuclear plant during certain accident scenarios, NRC officials said. There were no safety implications during the April 21 event, but there was a potential safety risk had an accident occurred while the valves were stuck open, they said..

“There was no immediate threat to public safety, but this event does raise important questions that need to be addressed,” Victor McCree, regional administrator for the NRC, said in a statement.

The agency's resident inspectors at Shearon Harris immediately began assessing the incident and are continuing to monitor Progress Energy’s activities. A four-member Special Inspection Team from the NRC’s regional offices in Atlanta and headquarters in Rockville, Md., will develop a timeline, review the utility's actions leading up to the event, examine the performance history of the valves and evaluate the company’s response.

Progress Energy is conducting its own review of the incident and will make any necessary repairs, spokesman Mike Hughes said. The repairs will be completed before the plant is restarted from its current refueling and maintenance outage, he said.

The NRC inspection will take several days, and a report documenting the results is expected to be issued within 45 days, officials said.