Rancho Seco Nuclear Generating Station
| Company type | Decommissioned nuclear power plant |
|---|---|
| Industry | Energy |
| Founded | 1975 |
| Defunct | 1989 |
| Headquarters | Herald, California , United States |
| Products | Electricity |
| Owner | Sacramento Municipal Utility District (SMUD) |
The Rancho Seco Nuclear Generating Station is a decommissioned nuclear power plant that was developed by the Sacramento Municipal Utility District (SMUD) and located in Herald, California.
History
In 1966, SMUD acquired land in southeast Sacramento County with the intention of constructing a nuclear power facility. This site was established in Herald, situated to the southeast of Sacramento.
During the early 1970s, a modest pond near the site was enlarged to form a lake intended as an emergency water reserve for the plant. This reservoir, supplied by the Folsom South Canal, was not utilized for the plant’s routine water needs. The area around the lake spans , providing recreational space initially overseen by Sacramento County.
The facility featured a 2,772 MWt Babcock & Wilcox pressurized water reactor with an electrical output of 913 MWe. It reached criticality on September 16, 1974, and commenced commercial operations on April 17, 1975.
On March 20, 1978, an electrical failure affecting the plant’s non-nuclear instrumentation led to steam generator dryout and triggered an automatic shutdown of the reactor. The U.S. Nuclear Regulatory Commission later classified this event as one of the most severe safety incidents in U.S. nuclear history, attributing it to known design deficiencies that had not been rectified in time.
Rancho Seco operated from 1975 until 1989 but maintained a lifetime capacity factor below 40%. The facility was ultimately closed following a public referendum that passed by a margin of 53% to 47%, primarily due to financial concerns: electricity costs had doubled over four years because of expensive plant upgrades, whereas natural gas-generated power remained less than half as costly (2.3 cents/kWh compared to 5.4 cents/kWh).
Although all generating machinery has been dismantled, the cooling towers still stand and are recognized as the tallest structures within California’s Central Valley. Presently, the site accommodates an 11 MW solar power installation, a larger 160 MW solar array inaugurated in 2021, and the Cosumnes Power Plant—a natural gas-fired facility with a capacity of 600 MW that began operation in 2006 and represents SMUD’s largest individual power source.
On October 23, 2009, the Nuclear Regulatory Commission released most of the property for unrestricted public access; however, approximately remains under NRC jurisdiction for low-level radioactive waste and spent fuel storage.
A study featured in Biomedicine International indicated a notable decline in cancer incidence within Sacramento County between 1988 and 2009, suggesting this trend might be partially associated with the plant’s shutdown and consequent reduction in nuclear emissions. Nevertheless, this finding has been disputed by experts who highlight possible methodological shortcomings in the research.
The original construction cost of the plant amounted to $375 million in 1974 dollars (equivalent to $ adjusted), while decommissioning expenses were approximately $120 million in 1974 dollars (equivalent to $ adjusted).
See also
- Rancho Seco Recreational Park
- S. David Freeman, former head of SMUD who played a key role in the plant's shutdown.
External links
- Articles with short description
- Nuclear power plants in California
- Buildings and structures in Sacramento County, California
- Sacramento Municipal Utility District
- Former nuclear power stations in the United States
- Nuclear power stations using pressurized water reactors
- Energy infrastructure completed in 1975
- 1975 establishments in California
- Energy infrastructure closed in the 1980s
- 1989 disestablishments in California