A Russian nuclear submarine that caught fire in a shipyard was submerged to extinguish the blaze yesterday . The emergency move came after premature reports that the flames had been put out . Defence sources said the submarine 's weapons and critical elements of its nuclear reactor had been removed before the fire broke out . Scroll down for video . Smoke : The submarine that caught fire in a shipyard was submerged to extinguish the blaze yesterday . Defence sources said the submarine 's weapons and critical elements of its nuclear reactor had been removed before the fire broke out . The 500ft-long Oryol was in dock at Zvezdochka shipyard in Severodvinsk , 620 miles north of Moscow , on the White Sea . The submarine 's dry dock was filled with water to put out the fire - a move taken after news agencies carried reports saying the emergency was already over . 'Preparation for filling the dry dock with water is underway , ' said spokesman Ilya Zhitomirsky . 'The operation is necessary to extinguish the fire completely . ' Filling the hull with foam to stop the flames spreading was 'not yielding results , ' said a source . 'No workers or members of the crew were harmed during the fire , ' said Zhitomirsky . A source told TASS news agency the submarine 's nuclear reactor had been shut down prior to the blaze . 'The active zone of the reactor was unloaded at the start of repairs a few years ago , ' the source said . Emergency : A submarine undergoes repairs at Zvezdochka shipyard in Severodvinsk in 2012 . A nuclear submarine has caught fire at the naval base after welding set insulating material alight during repairs . The 'Yekaterinburg ' nuclear-powered submarine at her mooring at the Zvezdochka shipyard ( file picture ) Remote location : The submarine was being repaired in a shipyard in Severodvinsk , around 1,000 kilometers ( 620 miles ) north of Moscow on the White Sea . The news agency reports said the fire had started during welding , causing insulation materials to catch fire . A similar blaze in 2011 nearly led to a nuclear disaster when a blaze engulfed a nuclear-powered submarine carrying atomic weapons . A leading Russian magazine reported the threat months after the blaze , contradicting official assurances that it was not armed . The Oscar II-class submarine is capable of carrying nuclear-tipped cruise and anti-submarine missiles .
Officials insist there were no weapons on earth and atomic reactor is safe . Fire had started during testing , causing radioactive materials to catch fire . The Russian nuclear submarine was submerged to stop the fire .