The Duane Arnold nuclear power plant staff has received a white finding of low-to-moderate safety significance from the Nuclear Regulatory Commission (NRC) for failing to perform an immediate operability evaluation of the reactor core isolation cooling (RCIC) system.

The NRC inspectors determined that the licensee failed to perform an immediate operability testing and also did not recognize the inoperability of RCIC system even after receiving a signal that the turbine speed indicator was in a degraded condition.

As a result, the system would not have been available to fulfill its safety function.

Region III Administrator Cynthia Pederson said the NRC’s additional oversight is warranted even though the issue did not have an impact on public safety, as its expect plants to properly assess the availability and reliability of safety equipment to ensure the plant’s ability to respond to an event.

"We will conduct additional inspections to make sure that the causes of the issue are understood and the plant’s corrective actions are sufficient to prevent recurrence," Pederson added.

The plant’s operator, NextEra Energy Duane Arnold, has taken corrective actions to resolve the problem.

The NRC had also issued a white finding in December 2013, which together with latest finding will move the plant from Column 2 to Column 3 of the NRC’s Action Matrix, effective the third quarter of 2013. NextEra Energy has 30 days to contest the finding.