The 2,772 MWt Babcock & Wilcox pressurized water reactor (913 MWe) achieved initial criticality on September 16, 1974, and entered commercial operation on April 17, 1975.

[3] On March 20, 1978, a power supply failure for the plant's non-nuclear instrumentation system led to steam generator dryout (ref NRC LER 312/78-001).

“In summary, the information was available and known which could have prevented this overcooling transient; but in the absence of adequate plant modifications, the incident should have been expected,” the staff wrote.

[7] The plant operated from April 1975 to June 1989, with a lifetime capacity factor of less than 40%; it was closed by public vote in June 1989 (53% to 47%) after half of its intended lifetime primarily for economic reasons: ratepayers had seen their rates doubled in the last four years to pay for improvements to the plant, and electricity from natural gas was priced at half that of the electricity generated by Rancho Seco.

[4] Also scattered throughout the area around the plant are abandoned civil defense sirens that at one time would have warned people of a radioactivity release from the station.