The Leak of the San Onofre Nuclear Reactor

Kaitlyn Albertoli
March 18, 2019

Submitted as coursework for PH241, Stanford University, Winter 2019


Fig. 1: This is the sky view of the San Onofre Nuclear Generating Station. (Source: Wikimedia Commons)

The San Onofre Nuclear Generating Station (SONGS), constructed in the 1950s, was intended to provide an additional source of sustainable power in San Clemente, California. SONGS can be seen from an overhead visual in Fig. 1 as it existed in 2012. The ballooning population in Southern California (between 10 million to 40 million people) created a pressing demand for a greater power source. Therefore, SONGS was constructed with that in mind. Nuclear energy was relatively new in the US at that time, so the plant started out with just one unit (Unit 1) as a testing opportunity for the plant prior to expansion. In the first decade, Unit 1 was operating at 70-75% efficiency, which was far greater than originally anticipated. By 2000, the plant was supplying 2.5% of SCEs electricity and 3% of SDG&Es energy. [1] This clean energy proved to be a cost- efficient solution as well as a scalable option.

The Problem

In the later part of the 1980s, SONGS contracted two more units, units 2 and 3 in order to boost production to meet the increasing Southern California demands. After the construction of the new units, unit 1 started facing extreme maintenance needs. Until this point, utility managers did not know how long the components of the plant would last and continued with merely good enough renovations and fuel rod replacements. After a cost-benefit analysis in 1991, SCE determined there were about $125 million in renovation costs (needed before end of year) associated with keeping the plant up to standard with the newest technologies and economic advances, several of which had been implemented into units 2 and 3. In combination with the heavily decreased efficiency rate, now only generating power at 51%, experts looked into the possibility of decommissioning the unit with the hope of reconstructing a new one in the future. [1]

Given the problems with deterioration of unit 1, it would make sense that both SCE and SDG&E would put more emphasis on up keep for their new units 2 and 3. Unfortunately, similar challenges arose with the aging of units 2 and 3. That being said, unlike the treatment of unit 1, SCE decided to completely overhaul the reactor system in the early 2000s, in order to avoid the inefficiency from outdated equipment. Between 2009 and 2011, new steam generators and other upgrades were attempted to the tune of $670 million. The goal was to tackle the potential maintenance needs before they became significant, which would have saved unit 1 if they had done so at the time. Yet, in January 2012, right after these new renovations, SONGS faced a small leak of radioactive gas, prompting an emergency shutdown. This leak confirms any fears or suspicions that residents have had about the plant and the risks associated with nuclear technology. [2,3]

The Impact

As a result of the leak, SONGS decided to shut down for the final time in 2012 in order to prevent a larger nuclear leak. During early 2012, unit 3 failed a pressure test on 7 tubes in its relatively new equipment. This demonstrated the continual inefficiencies of the plant and the incredible costs associated with its maintenance. Given the taxpayers had just helped fund the $670 million renovation, it did not make sense to continue the operation. The plant began its dismantling process in 2013, but this comes with an estimated cost of $4.4 billion for the dismantling as well as 1700 tons of nuclear waste that have to be properly managed. [4,5]


In conclusion, the continual development of nuclear technology will only continue to improve its efficiency. Further, the further development will lend to more cost-effective equipment and replacement materials, which would make these plants more sustainable in the long-term. From a consumer perspective, especially in Southern California, the need for a more sustainable electricity source is incredibly necessary, especially since the closing of the San Onofre Nuclear Generating Station.

© Kaitlyn Albertoli. 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] T. Gorman, "San Onofre Plant's Unit 1 to Shut Nov. 30 : Power: Oldest Commercial Nuclear Generator in State Will Be Decommissioned Because of Costs," Los Angeles Times, 10 Oct 92.

[2] P. Brennan, "San Onofre Nuclear Plant to Shut Permanently, Edison Says," Orange County Register, 8 Jun 13.

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

[4] T. Sforza, "Why Not Everyone's Happy about San Onofre's $4.4 Billion Teardown," Orange County Register, 21 Dec 16.

[5] G. Farley, "Decommissioning the San Onofre Nuclear Generating Station," Physics 241, Stanford University, Winter 2017.