The Shutdown of the San Onofre Nuclear Generating Station

Kathryn Plummer
March 8, 2019

Submitted as coursework for PH241, Stanford University, Winter 2018


Fig. 1: Aerial View of the San Onofre Nuclear Generating Station. Wikimedia Commons

The San Onofre Nuclear Generating Station (SONGS), shown in Fig. 1, is located in San Diego County in Southern California, near both Los Angeles and San Diego. The plant opened in 1968 with its first Unit. It then expanded in 1983 with Unit 2 and again in 1984 with Unit 3. [1] There were improvements completed in 2010 and 2011 when four replacement steam generators, manufactured by Mitsubishi Heavy Industries, were brought in. [2] The facility is owned by Edison International (78.2%), San Diego Gas and Electric (20%), and the City of Riverside (1.8%). [1] In 2012, SONGS provided 20% of Southern California's power, with the other margins coming from natural gas and other forms of renewable energy, such as wind and solar, which are thought to underwrite the construction of new nuclear power plants. [3] This plant has had some technical and maintenance problems over the years and has reduced the ability to produce safe, useable power.

Why Was SONGS Initially Shut Down?

In January 2012, Unit 2 was having routine scheduled steam generator inspection. In the same month, Unit 3 was diagnosed with a tube leak, that was leaking 82 gallons per day. Unit 3 was then shut down due to plant protocol and procedure. [2] With further inspection, it was uncovered that both Units 2 and 3 had rapid degradation of the generator tubing, most likely caused by rubbing against support structures and other tubing. [3] This malfunction of the tubing was caused by a design flaw, that miscalculated steam velocities within the generators. This is what initially caused the breakdown. The plant wasn't allowed to open, due to safely concerns, until the leak and degradations were found, understood, and fixed. Unfortunately, this never happened, and the units were decommissioned in 2013. [3]

Economic Implications and Safety Issues

The loss of SONGS has pushed up electricity prices in Southern California to about $4.15 higher than that of Northern California. Over 1,500 people lost jobs due to the shutdown. [1,3] Edison, the prime owner of the plant, was going to try to keep it open, but once they realized that opponents to the plant wanted the incident to go to a public hearing, they decided that it was going to be a cheaper investment to retire the plant. They would no longer have to provide for the workers of the plant or the maintenance. Edison had $2.7 billion saved for the decommissioning of the plant, which was about 90% of the required amount. [1] The closure of the plant obviously changed the forecast for many people in the surrounding area because so many people were now out of work. When the plant was first opened, it changed lives, and it is now doing the same but in the opposite way. The safety issues concerning the plant were plentiful. Opponents did not nuclear waste being stored, radioactive material becoming a health hazard, or poor evacuation plans. Complaints were sent to the NRC (Nuclear Regulatory Commission) in 2012, and eventually the NRC said that the plant could not reopen unless the owners developed a plan to fix and maintain the degraded steam generator tubes and until the NRC came and inspected the plant. [2,4] The plant was not able to be fixed, so it closed its doors officially in June 2013. The decommissioning would take over 20 years and cost more than $4.4 billion, and fuel wold be held in the tanks forever. [1,2,4]

© Kathryn Plummer. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] M. Wald, "Nuclear Power Plant in Limbo Decides to Close," New York Times, 7 June 13.

[2] "Memorandum and Order (Resolving Issues Referred by the Commission in CLI-12-20)," U.S Nuclear Regulatory Commission, "LBP-13-07," 13 May 13.

[3] M. Lee, "A Year Off the Grid," San Diego Union Tribune, 26 Jan 13.

[4] K. Carusa, "The San Onofre Nuclear Generating Station," Physics 241, Stanford University, Winter 2017.