It was not a pleasant sight for hundreds of onlookers at the Zvezdochka shipyard in Russia's Arkhangelsk region overnight when an Oscar II-class nuclear sub undergoing repair work suddenly caught on fire. According to RIA, which cited a spokesman for the shipyard, Evgeny Gladyshev "the fire started in the ninth section of the sub close to the stern. All the personnel left the submarine and fire brigades are currently dousing the flames." Oryol submarine fire photos via https://twitter.com/fotoflota!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");. http://t.co/KL6afi4weZ — Roland Oliphant (@RolandOliphant) https://twitter.com/RolandOliphant/status/585427532754903041!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); ?? ????????????? ?????? «?????????» ? ????????????? ?????????? ???????? http://t.co/RcHV1uZ09Q pic.twitter.com/eUwFguLYrx — #????????????? (@govoritmsk) https://twitter.com/govoritmsk/status/585423501022130176!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); ??? ???? ???????????? ?? ?????????????: http://t.co/4k0l0F3gaJ pic.twitter.com/I1eY2Yi3vv — ??????? ?? ?????? (@flashnord) https://twitter.com/flashnord/status/585427035805351936!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); A photo and a schematic of the Oscar II class submarine is shown below. The location of the Zvezdochka shipyard is shown below: As RT adds, the fire broke out onboard the K-266 Oryol, an Oscar II-class nuclear-powered submarine, which is part of Russia’s Northern Fleet. The shipyard is overhauling the sub to prolong its active service, so its nuclear reactor was shut down and its weapons unloaded before the repair works started. The Oryol entered service in December 1992. It was transported to the shipyard in November 2013 for a scheduled overhaul, which is to last until 2016. Here is the Oryol submarine undergoing maintenance in this mid-March photo. Preliminary reports say the fire was caused by a welding accident, which resulted in the ignition of the rubber insulation between the sub’s two hulls, according to Gladyshev. The photo below shows an Oscar II class submarine docked at the shipyard. As RT further reports, Oscar II submarines, designated Project 959A Antey in the Russian Navy, are designed to attack aircraft carrier groups with P-700 Granit (SS-N-19 Shipwreck according to NATO designation) supersonic cruise missiles as their primary weapons. A total of 11 such submarines were built. The nuclear sub Kursk that sank in August 2000, killing all submariners aboard, belonged to this class. Two others were decommissioned while the others remain in active service. This is not the first time in recent years Russia has had a similar maintenance accident: a similar fire at a nuclear submarine occurred in Russia in December 2011, when the K-84 Yekaterinburg of Delta-IV class caught fire during welding works at a shipbuilding dock. The fire, which was caused by a violation of safety guidelines, first ignited scaffolding around the sub and later spread to the insulation between its hulls. The massive fire, which lasted for some 20 hours, left nine people injured after inhaling toxic fumes and caused dozens of millions of dollars worth of damage. This time, there was no reported injuries and there was no estimate of the damage as of this moment. Which is lucky, because as the following video shows, the raging fire appears to have been in close proximity to the sub's nuclear reactors and the outcome could have been significantly worse.