While it may never happen, the danger of flooding at Duke Energy’s Oconee Nuclear Station in South Carolina is higher than previously thought.
In a report, the Nuclear Regulatory Commission (NRC) notified the Charlotte-based utility about the risks. The report found estimates of flooding have increased substantially if the 385-foot high Jocassee Dam failed upstream from the three reactors near Seneca, SC. The report also warns such flooding could leave the station blacked out.
The NRC removed large parts of the report from the public version in order to protect infrastructure that could become a security target.
Duke said Oconee is safe and the utility has taken steps to reduce flood risks.
The NRC began a formal study of the safety implications of dam failure on nuclear plants in March.
Last December, regulators found a backup safety system at a the plant wouldn’t have worked even if they needed it.
That finding meant the NRC increased its oversight and inspection of the plant.
Oconee plant employees found testing on the standby shutdown facility pressurizer heater breakers was not successful and the breakers were operable but degraded.
A special inspection team from the NRC then went down to the plant and evaluated the problem and issued a report.
The standby shutdown facility needs to shut down the plant in case something like a tornado or flood hits and they cannot use normal shutdown modes.