Human error caused the shutdown of one of Indian Point's two nuclear reactors on Wednesday, according to officials who are preparing to put the unit back on line as early as this weekend.
The incident arose while electrical technicians were performing regular periodic testing at Indian Point 2 based on steps outlined in a work order from the facility's engineers.
But because of the way it was described in the work order, the technicians did not realize that when they went to isolate one valve, two others would open, Nuclear Regulatory Commission (NRC) spokesman Neil Sheehan explained Friday.
When operators in the control room saw what was happening, they manually shut down the reactor, Sheehan added. No radioactivity was released but he said that the NRC would expect plant owner Entergy Corp. to review its training procedures "to make sure they don't have a repeat of this."
While everyone at the Buchanan facility acted "appropriately" and there were no equipment problems, "workers in the planning process for this test should have caught the effect that this test would have on the valve," said Entergy spokesman Jerry Nappi, adding that "the shutdown was avoidable."
Indian Point 2 will be up and running on either Saturday or Sunday, he said.
Indian Point 3, the other active reactor at the 250-acre plant, has been operating at full power without interruption.
The entire facility, which has 1,200 workers, supplies 25 percent of the electricity used in Westchester County and New York City.