Russian emergency workers extinguished a blaze in a shipyard on the White Sea after welding sparks ignited a fire Tuesday on a nuclear submarine.

Russia's Defence Ministry said there was no longer nuclear fuel aboard the vessel, which was located in a dry dock at the Zvezdochka shipyard in Severodvinsk, 1,300 kilometres north of Moscow.

The ministry said its reactor had been switched off more than a year ago and there was no danger of radiation.

The U-boat had been in dry dock since the end of 2013 for repairs to its hull.

Ivan Blokov, director of Greenpeace in Russia, said the incident raised alarms and that even if no radiation danger exists, the accident signaled a need to shift away from nuclear power.