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ROSEMEAD, Calif., November 1, 2011 —Southern California Edison (SCE) has contained an ammonia leak at the San Onofre Nuclear Generating Station, which resulted in an alert being declared today.

The leak was in the non-nuclear section of the plant. No radioactive material was released and there was no immediate danger to the public.

The approximately 30 gallons of leaked ammonia is being collected in a basin underneath the tank that was designed for that purpose. The alert remains in effect.

At approximately 3 p.m. PDT, SCE declared the alert based on identifying the ammonia leak in Unit 3’s water purification system.

No injuries were reported at the plant. As a precaution, the company evacuated employees in the area near where the leak was found.  Other employees remain in other areas of the plant.

The alert was required because fumes could prevent access to certain areas of the plant.  The control room is staffed and fully operational, and both Units are operating safely.

An alert is the second lowest of four federal classifications for emergencies at commercial nuclear power plants. An alert is characterized by events that are in process or have occurred that involve an actual or potential impact on the level of safety of the plant.

SCE and offsite agencies have opened the San Onofre Joint Information Center, located at 14155 Bake Parkway, between Toledo Way and Trabuco Road in Irvine.  More details will be released as they become available.  News media are encouraged to go to the Joint Information Center for the most up to date information regarding events at the plant.

In accordance with pre-existing emergency plans, appropriate federal, state and local emergency organizations, including the Nuclear Regulatory Commission, have been notified.

Background Information

  • Nuclear plant emergency classifications are established by the Nuclear Regulatory Commission.
  • The San Onofre plant, located just south of San Clemente, Calif., consists of two pressurized water reactors, Units 2 and 3, similar in design to 69 of the 104 operating U.S. reactors.
  • San Onofre is jointly owned by SCE (78.21%), San Diego Gas & Electric (20%), and the City of Riverside (1.79%).

About Southern California Edison
An Edison International (NYSE:EIX) company, Southern California Edison is one of the nation’s largest electric utilities, serving a population of nearly 14 million via 4.9 million customer accounts in a 50,000-square-mile service area within Central, Coastal and Southern California.


Ammonia Leak Contained at the San Onofre Nuclear Generating Station