The Maine Yankee nuclear plant was crippled by an explosion and fire that severely damaged non-nuclear parts of the plant, the Nuclear Regulatory Commission said Tuesday.

The explosion at 6:32 p.m. Monday was accompanied by a hydrogen fire that was extinguished when firefighters pumped carbon dioxide into the building, said NRC spokeswoman Diane Screnci.No radiation was released during the incident, but the plant's steam turbine, electrical conductors and transformers were badly damaged, she said. There were no reports of injuries.

The blaze, caused when a hydrogen line ruptured, was put out about 10 p.m., but the damage from the fire and blast shut down the plant indefinitely, officials said.

The hydrogen is used as a coolant.