Radioactive water leaked inside Florida Power Corp.'s nuclear power plant for about 10 minutes Thursday night, but the utility said no radiation was released. No one was injured.
The water leaked out of a valve and was caught in a collection system that circulates the water back into the plant system, Florida Power spokesman Mark Jacobs said.
At 9:20 p.m., the utility declared an "unusual event," a condition which the U.S. Nuclear Regulatory Commission says could lead to a deterioration of plant safety.
The unusual event ended at 10:50 p.m.
Enough water to fill two bathtubs spilled from the valve in the 10-minute period, Jacobs said. Plant operators stopped the leak by diverting the water around the valve, effectively taking the valve out of service.
Jacobs attributed the leak to normal wear on the packing around the valve.
The water, which contains boron, is known in industry jargon as reactor coolant.
The coolant helps transfer heat from the reactor core to the turbines that generate electricity.
Kept under 2,200 pounds per square inch of pressure to prevent boiling, the reactor coolant is heated by being pumped through the reactor core.
Then the coolant is run through a series of tubes immersed in another water supply.
The hot coolant causes the second water supply to boil, creating a stream of steam that turns the turbine to generate electricity.