The unit 3 reactor at California's San Onofre nuclear plant began an unplanned shutdown Tuesday evening after sensors picked up a leak in one of the reactor's steam generator tubes.
The San Onofre plant is on the Pacific Ocean coast near San Clemente north of San Diego. It consists of two units, No. 2 and No. 3. No. 1 was shut down permanently in 1992. It is one of two nuclear plants that generate electricity in Southern California; the other is the Diablo Canyon plant in San Luis Obispo County.
There are 8.4 million people within 50 miles of the San Onofre Nuclear Generating Station - between San Diego and Los Angeles.
According to plant operator Southern California Edison: "The potential leak poses no imminent danger to the public or plant workers. There has been no release to the atmosphere."
UPDATE: The San Diego Union-Tribune reports:
San Onofre spokesman Gil Alexander said sensors... showing mildly radioactive water was leaking from one of two water systems in the steam generator apparatus of Unit 3.
The water that touches the radioactive fuel rods--the water that is now leaking--is sealed in a series of tubes that, in turn, transfer heat to boil water in the second course. That non-radioactive water becomes the steam that turns the massive turbine blades.
A third course of seawater condenses the steam in another part of the plant.
Alexander said it is the system with the contaminated water that shows evidence of leaking. All leakage is contained within the thick concrete containment dome, he said.
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