Four of the six nuclear reactors at France's Gravelines nuclear power plant were shut down after an intake pipe used to draw water for cooling from a canal became clogged with jellyfish, Reuters reported.

A nuclear power plant in northern France hit by a jellyfish invasion was getting back online on Wednesday, operator EDF said, with service restored at the first of four closed reactors.

A huge nuclear power station in France has temporarily shut down after a "massive and unpredictable" swarm of jellyfish swam into the cooling system.