Tripped turbine shuts down TMI reactor

HARRISBURG - The reactor at Three Mile Island, site of the nation's worst nuclear accident, shut down automatically on Wednesday without posing a safety hazard after a turbine was tripped, a federal nuclear regulatory spokeswoman said.

The shutdown just before 6 p.m. was apparently caused by a disturbance on the electrical grid that tripped the turbine, which is powered by steam inside the reactor to generate electricity, Nuclear Regulatory Commission spokeswoman Diane Screnci said.

"The plant responded normally, and it is stable," Screnci said. "There was no danger."

TMI spokesman Ralph DeSantis described the incident as "an offsite disturbance to the power grid." He said there was no emergency condition.

It was unclear when the plant would resume operation. A spokesman for the plant operator, AmerGen Energy Co. LLC, did not immediately return telephone messages seeking comment Wednesday.

The Unit 1 reactor previously shut down on Nov. 2 after a faulty instrument reading triggered the automatic safety precaution. No radiation was released as a result of the shutdown, officials said at the time.

Unit 1 opened in 1974.

TMI, located in Middletown, about 10 miles southeast of Harrisburg, was the site of the nation's worst nuclear accident when a partial meltdown occurred in the Unit 2 reactor in March 1979.