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San Onofre Shutdown, One Year Later

KPBS Special Coverage: Tune In To KPBS Midday Edition At 12 Noon For An In-depth Discussion On The San Onofre Shutdown.

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The San Onofre Nuclear Generating Station has been offline since a small radiation leak in January last year led to the discovery of excessive wear on hundreds of steam generator tubes that carry radioactive water. Southern California Edison predicts running the plant at low power will stop tube damage. Environmentalists argue the plant cannot run safely.

A Look Back At Key Events

  • When San Onofre Nuclear Generating Station was shutdown a year ago, we knew that a leak in a steam generator tube in unit 3 of the nuclear power plant released a small, non-hazardous amount of radioactive gas. Because of that, unit 3 was shut down.
  • Unit 2 was already offline for maintenance. Southern California Edison, which operates the plant, said once the problem was resolved it would take several days for the reactor to be restarted.
  • The first indication that this was more than a routine shutdown came in February when the Nuclear Regulatory commission recommended a follow-up inspection -- because the failing tubes were almost brand new.
  • Edition had installed Unit 2 steam generators in 2010 and unit 3 steam generators in 2011.
  • Meanwhile, ratepayers continue to pay for running the disabled San Onofre nuclear plant. Customers in the San Diego, Riverside and Orange County regions pay about $64 million dollars a month to run San Onofre.
  • In October, the California Public Utility Commission opened an investigation into whether customers should pay to operate the plant while it remains offline, and whether ratepayers should be reimbursed for what they've spent so far.
  • Earlier this week, the state regulator released a memo outlining the timeline of the investigation and what will be considered.

Southern California Edison says its plan to run the San Onofre Nuclear Plant at reduced power will stop tube damage. The Nuclear Regulatory Commission won't make a decision on Edison's proposal to restart the plant until April or May. But critics say the plant can't run safely. What are some of the top safety concerns over restarting San Onofre?


CPUC Scoping Memo

CPUC Scoping Memo

California Public Utilities Commission "scoping memo" outlines the schedule, issues and procedural requirements for Phase 1 of the Order Instituting Investigation.

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KPBS invited representatives from Southern California Edison, San Diego Gas and Electric, the City of Riverside and the California Public Utilities Commission to be on the program, all declined.

Statement From Southern California Edison:

Southern California Edison is confident that exhaustive research by global experts demonstrates the safety of SCE’s conservative plan to restart San Onofore Nuclear Generating Station. SCE welcomes the opportunity to review this independent analysis at public meetings next month, including a Nuclear Regulatory Commission (NRC) meeting on Feb. 12 in Capistrano Beach, CA. The NRC scheduled the meeting to review SCE”s plan to address steam generator tube degradation at San Onofre. In addition, SCE will share its tube wear insights at an NRC meeting and webcast Feb. 7 in Rockville, MD regarding nuclear industry steam generator tube wear experience.

In addition to participation in public meetings, SCE has demonstrated its transparency by giving the public easy access to more than 170,000 inspections and analysis that confirm the safety of the Unit 2 restart plan. SCE’s restart plant and supporting documents, including ongoing replies to the NRC, are available at

SCE has continued to emphasizes that a critical review by the NRC of the company’s plan to restart Unit 2 is important to both the public and SCE. Safety remains SCE’s top priority and we are confident that when implemented, the Unit 2 restart plan will get San Onofre Unit 2 back to providing reliable and clean energy to Southern Californians.


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