NRC critiques OIG report on Diablo Canyon feedwater system oversight

May 5, 2022, 12:00PMNuclear News

The Nuclear Regulatory Commission turned the tables a bit on its inspector general’s office this week, releasing its response to a March 25 OIG event inquiry that criticized an NRC inspection at California’s Diablo Canyon nuclear power plant, performed after a July 2020 auxiliary feedwater (AFW) system failure at Unit 2.

The response highlights a number of what the agency terms “factual errors” and takes issue with several portions of the OIG report.

The response: Findings outlined in the NRC response include:

  • The leak in the AFW system did not cause the plant to shut down as stated by the OIG, nor did it compromise plant safety. The Diablo Canyon plant has operated safely and continues to do so.
  • The staff found no evidence that the AFW pipe corrosion hidden under metal-jacketed insulation should have been identified by NRC inspectors before the leak occurred. The resident inspectors then assigned to Diablo Canyon followed appropriate guidance during their inspection of the system, and regional and headquarters management appropriately determined that the leak had very low safety significance. Corrosion under insulation, which caused this leak, is known to the industry and the NRC.
  • The agency remains confident in the effectiveness of its inspection program, which is one of many ways in which it verifies nuclear power plant safety. Other methods include Reactor Oversight Program performance indicators, rigorous plant licensing requirements, robust design margins for every plant, redundant safety systems that provide defense in depth, and operator and training requirements to enable plant operators to respond to equipment malfunctions and unexpected events.

What they’re saying: “After reviewing the inspector general’s event inquiry, our technical staff determined that the Reactor Oversight Program and its associated inspection program continue to provide reasonable assurance of adequate protection of public health and safety,” stated Dan Dorman, the agency’s executive director for operations. “Resident inspectors are vital to the NRC safety mission. I have full confidence in the qualification, abilities, and professionalism of the inspectors involved in this event inquiry, as well as all of our inspectors.”


Related Articles

Maintaining RIPB in commercial LWRs

ANS Standards Committee publishes new standard for light water reactor risk-informed, performance-based design

September 29, 2022, 3:22PMNuclear NewsKent B. Welter

The new standard ANSI/ANS-30.3-2022, Light Water Reactor Risk-Informed, Performance-Based Design, has just been issued by the American Nuclear Society. Approved by the American National...

ANS Grand Challenge: Expedite licensing

September 22, 2022, 9:30AMNuclear NewsNicholas R. Brown

As the largest ultra-low-carbon electricity source in the United States, nuclear energy is a vital pillar of the effort to mitigate climate change. Deployment of advanced nuclear reactor and...

Advanced reactor licensing and the path to cost certainty

How Kairos Power is applying rapid iterative development to the licensing process as part of its strategy to deliver on cost

September 20, 2022, 3:13PMNuclear NewsMike Laufer

Developing a first-­of-­a-­kind reactor is a daunting endeavor. To be successful, advanced reactor designers need to achieve cost certainty by delivering a safe and affordable product at...

The “gold standard” of regulation

September 12, 2022, 3:04PMNuclear News

Much has been written about regulation over the years, including whether or not the nuclear industry is overregulated or whether the regulator is in the industry’s “pocket.” Having a...

The Future of Diablo Canyon

While many Californians are hopeful the state’s last nuclear power reactor can be saved, PG&E is actively preparing for decommissioning.

September 2, 2022, 3:00PMRadwaste Solutions

The reports of the death of the Diablo Canyon nuclear power plant may be greatly exaggerated. While Pacific Gas and Electric (PG&E) announced as early as 2016 that it would be closing...