Continuing to Learn the Lessons of San Onofre

Rebecca Sigmon
Reactor Systems Engineer
Office of Nuclear Reactor Regulation

Almost two years after the San Onofre nuclear power plant shut down permanently, the NRC has kept an eye on what we can learn from the events that led to the plant’s closure. The latest product of this work reviews the agency’s procedures related to Southern California Edison’s (SCE) installation of new steam generators at the plant.

songsThis work builds on our response to the steam generator damage San Onofre discovered in January 2012. At the time, our inspections and reviews aimed to understand what had happened and ensure public safety would be maintained before the plant could restart. Even after SCE decided in June 2013 to shut San Onofre down, the NRC continued its reviews to try to prevent something similar from happening at other reactors.

A year ago, our Executive Director for Operations asked the offices of Nuclear Reactor Regulation and New Reactors, as well as our Region IV office, to review the NRC’s own actions. The effort focused on the event and the NRC’s response to find any areas for improving our processes. The review covers issues raised in a 2014 NRC Inspector General report.

The review examines eight basic topics and discusses 17 actions to enhance what are already effective tools for overseeing U.S. operating reactors. Some of the topics include: better identification of potential design issues before they lead to problems; better assurance that plants comply with our requirements in 10 CFR 50.59, “Changes, Tests, and Experiments;” and improving communications with the public.

The review touched on all aspects of the NRC’s involvement in the San Onofre event, from on-site inspection to Congressional briefings, from technical review to website maintenance. The review team discussed some of these issues with industry experts. The team also sought comments from members of the public who participated in meetings about the San Onofre event and subsequent technical analyses.

The review concludes, among other things, that the 50.59 process is appropriate for plant activities that replace large components, such as steam generators. The review also finds that the staff properly used a Confirmatory Action Letter as an oversight tool in responding to the San Onofre events.

The staff’s already working on many of the review’s 17 actions. For instance, the staff is working on documents that clarify several areas of NRC guidance on following the 50.59 process. The NRC is also working on additional training for agency staff to improve their 50.59 reviews and associated activities. All of this ongoing work will help ensure U.S. nuclear power plants continue to safely operate, maintain and repair their systems.