The oversight was prompted by the staff’s failure to identify and correct a crack in a weld located in the Unit 1 high-pressure injection system that led to a leak. The leak led to reactor coolant system pressure boundary leakage and forced the shutdown of Unit 1. The high-pressure injection system provides water to cool the reactor during an accident if pressure in the system had remained high.
The crack was repaired, but the NRC determined that the method used to check for cracks did not provide acceptable coverage, nor did it identify the crack before it began leaking. The violation is determined to be “white,” or an incident of low to moderate safety significance. NRC staff said Duke has already taken corrective actions.
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