A reactor at the Indian Point nuclear power plant in New York shut down Monday night after an "electrical disturbance on the non-nuclear side of the plant," the company that runs the plan said in a statement.
The governor said that no radioactivity was released as a result of the 7 p.m. incident at the plant, about 25 miles north of New York City and said the cause was "unknown."
"I immediately directed the Department of Public Service to commence an investigation into another unexpected incident at Indian Point," he said.
In the statement, Entergy, which operates the facility, said that the disturbance caused the main electric generator and reactor to shut down "automatically and safely, as designed."
"Initial indications are that the electrical disturbance is related to a high voltage transmission line" that brings power from the plant to a switch yard.
The "precise cause" remains under investigation, the company said.