The Duane Arnold Energy Center near Palo, Iowa's only nuclear power plant, will have greater oversight by the Nuclear Regulatory Commission following problems with two backup systems in the last year.
The NRC on Wednesday said the plant will face more scrutiny and inspections after operators did not recognize the Reactor Core Isolation Cooling system was inoperable. The system, which is one of the sources of water for cooling the reactor in case of certain plant events, would not have been available to fulfill its safety function.
The agency said in case of an actual event, other systems would have provided cooling water to the reactor.
A second problem involved a backup diesel generator had an oil leak in March 2013. As a result, one of the plant's two diesel generators was inoperable.
The NRC and the plant's majority owner, NextEra Energy Resources, said public safety was never threatened by the concerns at the plant about 8 miles from Cedar Rapids. Renee Nelson, spokeswoman for NextEra Energy, said both problems were discovered by plant employees conducting inspections and were promptly repaired.
The NRC said it will conduct additional inspections to determine whether NextEra understands what caused the individual problems, whether there was a safety culture issue that led to the NRC findings, and what actions have been taken to prevent similar problems in the future.
"Even though the issue did not have an impact on public safety, the additional oversight by the NRC is warranted because we expect plants to properly assess the availability and reliability of safety equipment to ensure the plant’s ability to respond to an event,” said Region III Administrator Cynthia Pederson in a statement announcing its decision.NextEra Energy has 30 days to contest the NRC finding.