Report: Nuclear regulators failed to properly inspect Diablo Canyon Power Plant
SAN LUIS OBISPO COUNTY. Calif. - An investigation has revealed the Nuclear Regulatory Commission failed to properly inspect an important component at the Diablo Canyon Nuclear Power Plant.
The Office of the Inspector General released a report containing several findings regarding the NRC’s regulatory oversight of safety related structures and systems at the plant. One element focuses on the auxiliary feedwater system, which is a backup water supply that can be used to cool the reactor if normal feedwater is out of service.
The report states that after an auxiliary feedwater system failure that required one nuclear reactor to shut down for eight days, the Inspector General received specific allegations that the Nuclear Regulatory Commission had not properly inspected the system prior to the event.
The Inspector General's report revealed:
The NRC failed to identify piping insulation on the AFW system that had long been in a degraded condition, and that led to a leak. Our investigation further revealed that the NRC had not inspected the area where the leak occurred, even though its inspection report indicated that the inspectors had conducted a complete walkdown of the AFW system in April 2020, three months prior to the leak and shutdown. A complete walkdown is a physical inspection that verifies that the selected system is correctly aligned and able to perform its intended safety function. Our investigation also demonstrated that the number of hours NRC staff spent directly inspecting both reactors’ AFW systems for the complete walkdown in April 2020 was fewer than recommended in the applicable NRC inspection procedures.
Representative Salud Carbajal issued a statement on the report saying:
“The findings released today by the NRC’s Inspector General are unsettling and unacceptable.
“The safety and well being of the entire San Luis Obispo community relies on federal inspectors adhering to those safety protocols, and the negligence detailed in this report will erode the public trust in those who are tasked with keeping us safe.
“It is critically important that the NRC make a clear and convincing case to the Central Coast how it will hold their inspectors accountable for breaking protocol and how it intends to restore confidence in their operations at DCPP. In the coming days, I will be formally asking NRC leaders for specific details on why required inspections were not completed, what corrective actions will be taken, and what steps the NRC will take to enforce its regulations in the remaining time that DCPP is operational.”
Suzanne Hosn, a spokesperson for PG&E issued this statement on the findings:
Safety is and always will be our most important responsibility at PG&E and Diablo Canyon, and the plant has an excellent safe operating record. We identified this issue while Unit 2 was shut down for maintenance in 2020, made the repairs and conducted thorough inspections before the unit was returned to service. Additionally, we performed similar inspections on Unit 1 and identified no further conditions requiring repair.
We take issues about safety very seriously and take immediate actions to ensure we are always ready to meet our mission to protect public health and safety.
The report says improvements to the system have been made, and Diablo Canyon continues to operate safely.
