The floating plant, the Akademik Lomonosov, was towed out of the St Petersburg shipyard where it was constructed on Saturday.

It is to be pulled through the Baltic Sea and around the Norwegian coast to Murmansk, a city of 300,000 people, where its reactors are to be loaded with nuclear fuel.

The Lomonosov is to be put into service in 2019 in the Arctic off the coast of Chukotka in the far northeast, providing power for a port town and for oil rigs.

Rosatom, the state-owned atomic energy corporation, is the owner of the nuclear power plant.

The website of OKBM Afrikantov, the power equipment company responsible for the design of the reactors and other elements, lists the project as a "pilot design".

The vessel will have at least two nuclear reactors, according to World Nuclear News, of a type that are similar to those used on Russian nuclear-powered ice breakers.