San Onofre—Inside a Nuclear Power Plant Being Decommissioned, Part 1

The San Onofre Nuclear Generating Station, located on the Pacific coast of southern California near San Clemente, went into operation in 1968 with Unit 1. In 1983, Unit 2 went operational, and was joined in 1984 by Unit 3. With all units operating, the plant generated 2.2 gigawatts of electricity for its owners, Southern California Edison, San Diego Gas & Electric, and the City of Riverside.

In 1992, Unit 1 was retired after 25 years of service and began a decommissioning and dismantlement process, now complete. The site is now used for storage of spent fuel from Units 2 and 3. In 2009 and 2010, upgrades were made to Units 2 and 3 intended to equip them for 20 years of additional operation, but it was discovered in 2012 that new steam generators installed as part of the upgrade were defective and required replacement. Faced with a lengthy and costly regulatory and engineering process of replacement, the plant’s owners decided in 2013 to retire Units 2 and 3. Finally, around 2020, with all approvals from federal and California authorities in hand, dismantlement began.

The power once produced by the San Onofre reactors has been replaced by natural gas fired power plants and energy storage facilities.

This part tours the facility from the outside. A second part will visit the fuel processing pool and spent fuel storage facilities.