A transformer exploded yesterday at the Indian Point nuclear-power plant in Westchester, leading to an emergency shutdown of one of its reactors.

An official at the plant in Buchanan, about 45 miles north of New York City, said no one was injured in the 6:30 p.m. incident.

Jim Steets, a spokesman for the plant’s owner, Entergy Corp., said there was no fire and no radioactive material leaked.

He added the transformer was not near the reactor.