San Onofre Nuclear Generating Station

San Onofre Nuclear Generating Station
Name	San Onofre Nuclear Generating Station
Country	United States
Location	San Diego County, California
Status	Decommissioned
Operator	Southern California Edison
Construction	1958–1967
Commissioned	1968–1983
Decommissioned	2013–2025 (estimated)
Reactors	3 (Units 1–3)
Capacity	~2,200 MW (peak operational)

San Onofre Nuclear Generating Station is a retired nuclear power complex on the Pacific coast of California near the San Diego County–Orange County border. The plant played a central role in regional electricity supply, interplaying with entities such as Southern California Edison, San Diego Gas & Electric, and the California Energy Commission before its retirement, and its closure influenced debates among Nuclear Regulatory Commission staff, environmental organizations, and energy policy makers.

Overview

The facility sat adjacent to Camp Pendleton, near the San Onofre State Beach, within the coastal region delineated by Interstate 5, close to San Clemente, California, Oceanside, California, and Dana Point, California. Owned and operated primarily by Southern California Edison with participation by San Diego Gas & Electric and formerly Pacific Gas and Electric Company, the site connected to the California Independent System Operator grid and to transmission corridors involving Path 26 and Path 15. Nearby jurisdictions and stakeholders included California Public Utilities Commission, United States Marine Corps, City of San Clemente officials, and conservation groups such as the Sierra Club.

History and construction

Planning and construction occurred amid postwar expansion in the 1950s and 1960s when corporations like Edison International and contractors including General Electric and Westinghouse Electric Company supplied components. Unit 1 was developed amid licensing frameworks shaped by the Atomic Energy Commission, while Units 2 and 3 were built under oversight that later transitioned to the Nuclear Regulatory Commission after the Energy Reorganization Act of 1974. The site’s coastal siting prompted interactions with agencies like the United States Fish and Wildlife Service and state bodies such as the California Coastal Commission. Labor and engineering involved unions like the International Brotherhood of Electrical Workers and firms such as Bechtel Corporation. Key policy contexts included deliberations influenced by the National Environmental Policy Act and energy debates involving Federal Energy Regulatory Commission purviews.

Reactors and technical specifications

Originally Unit 1 was a small pressurized water reactor supplied by Westinghouse Electric Company, while Units 2 and 3 were larger Combustion Engineering pressurized water reactors with steam generator designs that later became central to controversy. Thermal–electric design tied into technologies from General Electric for turbines and partnerships with suppliers including Babcock & Wilcox for auxiliary systems. The cooling systems drew seawater from the Pacific Ocean and interfaced with marine infrastructure regulated under statutes like the Clean Water Act and overseen by agencies such as the Environmental Protection Agency. Instrumentation and control systems were influenced by standards developed by Institute of Electrical and Electronics Engineers committees and vendor practices from ABB Group. Safety analyses referenced criteria from the American Society of Mechanical Engineers and risk assessments comparable to studies by Oak Ridge National Laboratory and Sandia National Laboratories.

Incidents, shutdown, and decommissioning

Operational events included Unit 1 retirement in the early 1990s and later mechanical problems with Units 2 and 3 leading to the 2012–2013 premature cessation of generation. Technical investigations involved independent experts from Electric Power Research Institute and peer reviewers from Massachusetts Institute of Technology and University of California, Berkeley researchers. Litigation and regulatory reviews engaged the Nuclear Regulatory Commission, the California Public Utilities Commission, and courts where utilities such as Southern California Edison and San Diego Gas & Electric contested cost recovery with intervenors including Public Advocates Office and consumer groups exemplified by The Utility Reform Network. Decommissioning plans invoked contractors like EnergySolutions and coordination with the Department of Energy for long-term spent fuel storage policy debates tied to the defunct Yucca Mountain repository project and alternatives such as consolidated interim storage proposals advocated by entities including Holtec International.

Environmental and regulatory issues

Environmental impacts raised concerns from organizations like Natural Resources Defense Council, Heal the Bay, and the Surfrider Foundation about coastal ecosystems, marine life, and the Southern California Bight. Regulatory scrutiny intersected with state statutes enforced by California Environmental Protection Agency components, and federal statutes such as the Endangered Species Act. Stakeholders included tribal interests like the Juaneño Band of Mission Indians and research institutions such as Scripps Institution of Oceanography studying oceanographic effects. Policy debates referenced reports by Union of Concerned Scientists, analyses by the Lawrence Berkeley National Laboratory, and proceedings before the United States Court of Appeals for the Ninth Circuit.

Site redevelopment and legacy

Post-shutdown deliberations have considered reuse scenarios involving renewable energy developers like NextEra Energy and technology firms working on energy storage and microgrid projects associated with Tesla, Inc. battery systems and companies such as AES Corporation. Local planning engaged the City of San Clemente, County of San Diego, and the California Coastal Commission for land use and public access, with community groups including Friends of San Onofre Coast and historical advocates referencing the site’s role in regional industrial heritage. The facility’s legacy informs national debates involving Nuclear Energy Institute, energy transition discussions at the United Nations Framework Convention on Climate Change, and academic curricula at institutions like University of California, Los Angeles and California State University, Fullerton. Ongoing issues include spent fuel policy deliberations in forums such as the Blue Ribbon Commission on America’s Nuclear Future and regulatory practices at the Nuclear Regulatory Commission that affect future coastal nuclear proposals and decommissioning precedents.

Category:Nuclear power stations in California