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NRC NEWS U. S. NUCLEAR REGULATORY COMMISSION OFFICE OF PUBLIC AFFAIRS, REGION IV 611 Ryan Plaza Drive, Suite 400, Arlington TX 76011

NRC Monitors Unusual Event at Diablo Canyon

The U.S. Nuclear Regulatory Commission staff is closely monitoring conditions at Diablo Canyon, a nuclear power plant near San Luis Obispo, California, following an automatic reactor shutdown and declaration of an "Unusual Event" at the plant at 12:43 a.m. PDT.

At this time the unit 1 reactor has been safely shutdown. Because the reactor tripped from full power, steam was released to the atmosphere. The steam released could contain minute amounts of radioactivity well below federal release limits. No impacts to public health and safety are anticipated.

Events at the plant began at about 12:25 a.m. when a fault occurred in electrical cabling inside the Unit 1 turbine generator building. This resulted in a protective shutdown of the main generator followed by the unit 1 reactor trip. Plant operators declared a Notice of Unusual Event, which is the lowest emergency action level in the NRC required emergency response plan for nuclear reactors, shortly afterward.

Diablo Canyon operators are working to restore electrical power. There were no injuries and all reactor systems functioned properly during the shutdown and there are no significant complications at this time.

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