The US Nuclear Regulatory Commission’s latest assessment of nuclear reactor performance found that 91 of the 93 operating reactors in the US fell into the top NRC category for safety and security performance in 2021. Two reactors – Ameren Missouri’s Callaway and Energy Harbor’s Davis-Besse – fell into the second performance category, indicating the need for enhanced NRC oversight and corrective actions.
The NRC told Ameren early in 2021 that Callaway-1, a 1,215-MW pressurised water reactor in Missouri that began commercial operation in December 1984, had been moved to the “regulatory response” category as a result of having three unplanned scrams during the second through fourth quarters of 2020, combined with having lower than normal hours of critical operation for the year.
The NRC told Ameren early in 2021 that Callaway-1, a 1,215-MW pressurised water reactor in Missouri that began commercial operation in December 1984, had been moved to the “regulatory response” category as a result of having three unplanned scrams during the second through fourth quarters of 2020, combined with having lower than normal hours of critical operation for the year.
Davis-Besse-1, an 894-MW PWR in Ohio that began commercial operation in July 1978, was moved to the regulatory response category last year due to a greater-than-green finding (meaning a finding of more than very low safety significance) identified by NRC personnel during a scheduled cybersecurity inspection.
More recently, the NRC issued Energy Harbor a violation notice involving the failure to select a suitable replacement part for Davis-Besse’s emergency diesel generator speed switch. The speed switch design was not compatible with the station’s 125/250-volt direct current battery system, according to the NRC.
