A fire led to a blast in the machine room of a nuclear power plant in the Manche region of France in Normandy, its operator has said.
EDF said the fire at the Flamanville plant was "immediately" brought under control and there was no radiation leak or injuries.
The cause of the fire, in the number one reactor building, was not immediately clear.
The plant operator also said the reactor has been disconnected from the grid - as per normal operating procedures in such circumstances.
Flamanville has two 1,300 megawatt reactors, the first has been in operation since 1985, and the second since 1986.