The San Onofre Nuclear Generating Station (SONGS) is a permanently closed nuclear power plant located south of San Clemente, California, on the Pacific coast, in Nuclear Regulatory Commission Region IV. The plant was shut down in 2013 after defects were found in replacement steam generators; it is currently in the process of being decommissioned. The 2.2 GW of electricity supply lost when the plant shut down was replaced with 1.8 GW from new natural-gas-fired power plants and 250 MW from energy-storage projects.
The plant is owned by Southern California Edison (SCE). Edison International, parent of SCE, holds 78.2% ownership in the plant; San Diego Gas & Electric, 20%; and the City of Riverside Utilities Department, 1.8%. When fully functional, it employed over 2,200 people. Located between the Pacific Ocean and the Surf Line, the station is a prominent landmark because of its twin hemispherical containment buildings which were designed to contain any fission products in the event of an incident.
The plant's first unit, Unit 1, operated from 1968 to 1992. Unit 2 was started in 1983 and Unit 3 started in 1984. Upgrades designed to last 20 years were made to the reactor units in 2009 and 2010; however, both reactors were shut down in January 2012 after premature wear was found on more than 3,000 tubes in replacement steam generators that had been installed in 2010 and 2011. The Nuclear Regulatory Commission investigated the events that led to the closure. In May 2013, Senator Barbara Boxer, the then-chairman of the Senate Environment and Public Works Committee, said the modifications had proved to be "unsafe and posed a danger to the eight million people living within of the plant," and she called for a criminal investigation.
In June 2013, Southern California Edison announced the permanent retirement of Unit 2 and Unit 3, citing "continuing uncertainty about when or if SONGS might return to service" and noting that ongoing regulatory and "administrative processes and appeals" would likely cause any tentative restart plans to be delayed for "more than a year". The company stated, "Full retirement of the units prior to decommissioning will take some years in accordance with customary practices. Actual decommissioning will take many years until completion." Concerns continue over Edison's plans for on-site dry cask storage of the considerable amount of nuclear waste created during the facility's decades of operation.
During its operation until 2012, SONGS provided about 20% of the power to large portions of Southern California.
Description
The San Onofre Nuclear Generating Station (SONGS), operated by Southern California Edison (SCE) is approximately 100 km (60 mi) south of Los Angeles, 6.5 km (4 mi) south of San Clemente, CA. It is located between the Surf Railroad Line and the Pacific Ocean within Marine Corps Base Camp Pendleton.
Unit 1 commenced operation in 1968, and shut down in 1992. Unit 1, a first-generation Westinghouse pressurized water reactor that operated for 25 years, closed permanently in 1992; it has been dismantled and is used as a storage site for spent fuel. It had a spherical containment of concrete and steel; the smallest wall was thick. It generated 456 MWe gross, and 436 MWe net, when operating at 100% capacity.
Units 2 and 3, Combustion Engineering two-loop pressurized water reactors, generated 1,127 MWe gross, and 1,070 MWe and 1,080 MWe net respectively, when operating at 100% capacity. Units 2 and 3 permanently ceased operations in June 2013.
In a ten-year project completed in 2011 and costing $671 million, Edison replaced the steam generators in both reactors with Mitsubishi steam generators of the modified design. Because of the reactors' two-loop design, uncommon for such large reactors of that era, the steam generators were among the largest in the industry. A common shortcoming of these large steam generators was tube wear, requiring replacement earlier than their 40-year design life. The steam generators being the largest components in the reactor required a temporary hole through the concrete containment shell. The Unit 2 replacement was completed in 2009 and Unit 3 in 2011. Edison estimated that the modernization would save customers $1 billion during the plant's license period, which at the time ran until 2022.
Unit 1 Dismantlement of Unit 1 is essentially complete. The turbine building was removed and the licensee completed reactor pressure vessel internal segmentation and cutup; however, the licensee was unable to make arrangements for shipping the reactor pressure vessel to a disposal facility because of the size and weight of the vessel and shipping package. The licensee is making plans to ship the vessel offsite during the decommissioning activities for Units 2 and 3 because the radioactivity has decayed to a level that allows it to be treated as low level waste.
SONGS-1 was a Westinghouse 3-loop pressurized water reactor constructed by Bechtel and rated at 1347 MWthermal . It began commercial operation on January 1, 1968, and ceased operation on November 30, 1992. Defueling was completed on March 6, 1993. On December 28, 1993, NRC approved the Permanently Defueled Technical Specifications. On November 3, 1994, SCE submitted a Proposed Decommissioning Plan to place SONGS-1 in SAFSTOR until the shutdown of Units 2 and 3. On December 15, 1998, following a change in NRC decommissioning regulations, SCE submitted a post shutdown decommissioning activities report (PSDAR) for SONGS-1, to commence DECON in 2000. SCE actively decommissioned the facility, and most of the structures and equipment have been removed and sent to a disposal facility. The NRC issued a license amendment in February 2010 releasing the off-shore portions of the Unit 1 cooling intake and outlet pipes in place, under the Pacific Ocean seabed, for unrestricted use. The fuel from Unit 1 was transferred to Phase 1 of the independent spent fuel storage installation (ISFSI). In 2015, the ISFSI was expanded onto the area previously occupied by Unit 1 in order to store all Unit 2 and Unit 3 spent fuel. SCE completed transferring all of the nuclear fuel to dry storage in 2020.
The Unit 1 Reactor Pressure Vessel was transported via rail and then highway to the Energy Solutions disposal facility in Clive, Utah. The shipment left May 24, 2020 from San Onofre and arrived at the disposal facility on July 14, 2020.
Safety issues The San Onofre station had a range of technological problems over the years. In July 1982, Time wrote, "The firm Bechtel was ... embarrassed in 1977, when it installed a 420-ton nuclear-reactor vessel backwards" at San Onofre. In 2008, the San Onofre plant received multiple citations over issues such as failed emergency generators, improperly wired batteries and falsified fire safety data. In its annual review of 2011, the Nuclear Regulatory Commission (NRC) identified improvements but noted that in the area of human performance, "corrective actions to date have not resulted in sustained and measurable improvement".
According to the NRC, workers at San Onofre were "afraid they will be retaliated against if they bring up safety problems, something that's against the rules". As of 2011, according to the NRC, there had been progress on the issue and the problems were not considered a threat to the safety of plant workers or the public. In November 2011, there was an ammonia leak, and as a precaution company employees were evacuated from the leak area, while the units continued normal operation.
A mid-cycle inspection report spanning July 2011 to June 2012 revealed three incidents relating to human performance. An additional issue concerned a failure to develop procedures for a "cyber security analysis of electronic devices" that was later corrected.
In 2012, coolant fluid was found in the oil system of a backup diesel generator, which would have caused the generator to fail if needed. An internal investigation found "evidence of potential tampering", making sabotage by staff a possible cause.
Environmental risk and mitigation Southern California Edison stated after the Fukushima disaster in 2011 that the station was "built to withstand a 7.0 magnitude earthquake directly under the plant". Additionally, there was a to protect the plant from a tsunami which could be potentially generated by the active fault offshore. The closest tectonic fault line is the Christianitos fault, less than a mile away, which is considered inactive or "dead", but other active faults in the vicinity might pose some threat.
The NRC's estimate of the yearly risk of an earthquake intense enough to cause core damage to the reactor at San Onofre was 1 in 58,824, according to a study it had published in August 2010.
In June 2012 S. David Freeman, the former head of the Southern California Public Power Authority and "a longtime anti-nuclear voice", described San Onofre and Diablo Canyon as "disasters waiting to happen: aging, unreliable reactors sitting near earthquake fault zones on the fragile Pacific Coast, with millions of Californians living nearby".
The San Onofre plant used seawater for cooling, like some other seaside facilities in Southern California, lacking the large cooling towers typically associated with nuclear generating stations. Limited available land next to SONGS would likely have required towers to be built on the opposite side of Interstate 5.
Surrounding population The NRC defines two emergency planning zones around nuclear power plants: 1) a plume exposure pathway zone with a radius of , concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and 2) an ingestion pathway zone of about , concerned primarily with ingestion of food and liquid contaminated by radioactivity. The average prevailing westerly wind direction at San Onofre blows inland 9 months of the year.
The 2010 U.S. population within of San Onofre was 92,687, an increase of 50.0 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within was 8,460,508, an increase of 14.9 percent since 2000. Three of the cities within 20 miles of the facility are San Clemente and Laguna Beach in Orange County and Oceanside in San Diego County. San Diego is 45 miles south of the facility, and Los Angeles is 60 miles north of the facility.
Anti-nuclear protests, 1977–present
On August 6, 1977, about a thousand anti-nuclear protesters marched outside the nuclear generation station, while units 2 & 3 were under construction.
On March 11, 2012, more than 200 activists protested at the San Onofre Nuclear Generating Station to mark the one-year anniversary of the Fukushima Daiichi nuclear disaster. Two Japanese residents who lived through the Fukushima meltdowns and one-time congressional candidate Raymond Lutz spoke, saying the generators, which had been offline since January 2012, should remain off. In May 2012, environmental and anti-nuclear activists gathered at Southern California Edison's Irvine headquarters calling for the San Onofre plant to be decommissioned.
Shutdown (2012) and closure (2013)
Initial shutdown