10 milestones in the history of Diablo Canyon

PG&E announced Tuesday that it has decided not to pursue relicensing the two reactors at the Diablo Canyon nuclear power plant near Avila Beach in San Luis Obispo County. After opening in 1985, the plant will now close in 2025. Here’s a quick look at some important moments in the power plant’s history.

Feb. 27, 1963: PG&E announces it will build a new power plant in the Nipomo Dunes. The project is vehemently opposed by the Sierra Club and other environmentalists who want the dunes protected.

In 1968, ruins of an adobe sit near the site of the soon-to-be-constructed Diablo Canyon nuclear power plant. Tribune file photo

Sept. 27, 1966: PG&E selects Diablo Canyon over the Nipomo Dunes as a site for a nuclear power plant.

Diablo Canyon is under construction in this aerial photo from 1972. Larry Jamison - The Tribune

April 1968: Atomic Energy Commission approves the construction permit for Unit 1 of Diablo Canyon.

Dec. 17, 1973: The U.S. Geological Survey confirms a fault has been found offshore of Diablo. It turns out that the fault had been discovered in 1969 and mapped in a 1971 paper by two Shell Oil geologists, Ernest G. Hoskins and John R. Griffith. It was named the Hosgri Fault in their honor.

A group of anti-nuclear protesters wave a flag above the Diablo Canyon nuclear power plant in September 1981. Thousands of people were arrested during a blockade of the plant. Ken Chen - Telegram-Tribune

Sept. 15, 1981: Abalone Alliance blockade of Diablo Canyon begins. It continues two weeks and results in nearly 2,000 arrests.

Sept. 28, 1981: Discovery of “mirror image” blueprint error delays opening of Diablo Canyon by more than three years.

May 7, 1985: Unit 1 begins commercial operation.

June 2, 2000: California water officials and PG&E announce a settlement for damage Diablo Canyon’s warm water discharge does to the ocean. It calls for PG&E to pay $4.5 million for marine restoration projects and to preserve an undisclosed amount of coastal land between the power plant and Montaña de Oro State Park.

These above-ground casks are designed to store radioactive waste from a nuclear reactor at Diablo Canyon Power Plant in Avila Beach. Michael A. Mariant - The Associated Press

Oct. 23, 2008: The Nuclear Regulatory Commission rules that PG&E can begin loading used reactor fuel into an above-ground dry cask storage facility.

June 7, 2011: PG&E moves to suspend license renewal application filed with NRC amid concerns about the Fukushima nuclear disaster and the seismic safety of Diablo Canyon. Following completion of seismic studies, the NRC later began reprocessing the application.