The Nuclear Regulatory Commission has scheduled a conference with Duke Energy officials on July 31 to discuss an apparent violation at the Oconee Nuclear Station.
NRC spokesman Roger Hannah said at issue is a crack in a weld on the Unit 1 high pressure injection system at the station. The crack forced a temporary shutdown back in November. The systems pumps water to cool the reactor if the pressure to that injection system remained high.
“That system would provide cooling water to the reactor core in the event of some accident scenario,” Hannah said. “It was not needed and they repaired the crack, but the violation arose after we determined that the crack should have been identified earlier.”
Duke Energy operates the Oconee plant near the town of Seneca.
Officials said there was no immediate safety concern because the crack was repaired. However, Hannah said the NRC determined that the method used by the plant to check for cracks did not provide acceptable coverage as required and did not identify the crack before it began to leak.
“They do ultrasonic testing of these kind of piping and systems and they should have found this crack,” he said. “They didn’t identify it as early as they should have under the regulation and that is why there is an apparent violation.”
Hannah said one of the expected outcomes of the conference is how to classify of the apparent violation. The NRC evaluates regulatory performance at commercial nuclear power plants with a color-coded system which classifies findings as green, white, yellow or red, in increasing order of safety significance.
“We now categorize it as greater than green, which means, at least under a preliminary basis, we have determined that it has greater than low safety significance. We haven’t given it a color beyond that and won’t do that until we look at all the information, including the information provided by Duke Energy on the 31st.”
The conference is scheduled for 9:00 a.m. on July 31 at the NRC’s Region II office in Atlanta. Officials said no decisions on the final safety significance or any additional NRC actions will be made at the conference.