CHARLOTTE — Federal inspectors have told Charlotte-based Duke Energy they’ve found safety problems at the Catawba Nuclear Station in York County, S.C.
The Charlotte Observer reported the problems could lead to more inspections of the plant on Lake Wylie on the South Carolina-North Carolina state line.
The plant lost incoming power April 4. Backup generators kicked in and the one operating reactor shut down safely. The other reactor already was shut down for refueling.
The utility is reviewing the report from the Nuclear Regulatory Commission, said Mary Kathryn Green, a Duke spokeswoman.
Investigators traced the problem to a programming error when electrical changes were made on Unit 1 last July and November and to Unit 2 in February. The error meant off-site power would be inadvertently lost anytime the units’ generator shut down because of a power fluctuation.
A ground fault on a reactor coolant pump triggered the reactor, turbine and generator to stop during the April 4 incident.
Losing the off-site power removes the primary energy source for the plant operations, including the system that keeps cooling water circulating.
The problem has been corrected, Green said.
Both reactors are now at full power.
Regulators initially classified the problem as having substantial safety significance. Duke will present its case at a public meeting.
If the NRC keeps the current classification of the problem, there would be an additional 200 hours of inspections to ensure the problem has been resolved, agency spokesman Roger Hannah said.