The San Onofre Nuclear Generating Station

Reed Miller
March 17, 2015

Submitted as coursework for PH241, Stanford University, Winter 2015

History of the Plant

Fig. 1: The San Onofre Nuclear Plant, viewed from the beach. (Source: Wikimedia Commons)

Beginning its comercial operation in 1968, the San Onofre Nuclear Generating Station (SONGS, see Fig. 1) is located within the Camp Pendleton Marine Corps Reservation, right on the coast of the Pacific Ocean. Located just 50 miles north of San Diego and 60 miles south of Los Angeles, over 500,000 people live within 25 miles of the plant, with over 5,000,000 living within 50 miles (as of 1983). [1] Opening a second unit in 1983, and a third in 1984, SONGS operated on all three units until Unit 1 was retired in 1992 due to repair costs. As of the year 2000, the plant was approved to operate until 2022, but problems arose. In September of 2009, the it was revealed that there was "staff misconduct and falsified records" within the Onofre plant. In January 2012 Unit 2 was taken offline for routine maintenance, but "a small radiation leak in the Unit 3 on Jan. 31 triggers a complete shutdown of the plant and helps uncover rapid wear on tubing within recently replaced steam generators." On June 7, 2013, Southern California Edison announces it will close the nuclear plant due to repair costs rising to over $550 million and the federal government being indecisive over whether or not to approve the plant for operation. [2]

Decommissioning and Impact

As SONGS is slowly decommissioned, one cannot help but look back at what could have happened should something have gone wrong. The only notable leak prior to 2013 came in 1972, with "the total gaseous discharge was less than 20,000 curies over a one year period." [1] To put how little that is in perspective, there was " no measurable increase in the off- site radiation exposure relative to the natural background radiation." [1] But, as mentioned in the beginning of the mortality patterns report from 1983 (see sources), a category 4 incident could have resulted in approximately 835 additional radiation-based cancer deaths in every 500,000 people near SONGS. [1] With data from the 2013 United States Census, roughly 6,000,000 people lie within the danger zone of the Onofre plant. That would equate to about 10,020 deaths if a category 4 incident took place around 2011. [3,4] It is for this reason that the San Onofre Nuclear Generating Station was not approved for recommission in 2013.

© Reed Miller. 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] J. E.Enstrom, "Cancer Mortality Patterns Around the San Onofre Nuclear Power Plant, 1960-1978," Am. J. Public Health 73, 83 (1983).

[2] "Timeline of San Onofre Plant's Pperations," U-T San Diego, 7 Jun 13.

[3] "San Diego County Demographics Profile, North Central Region, 2011 Population Estimates," County of San Diego, March 2013.

[4] "Profile of Orange County," Southern California Association of Governments, May 2013.