There appears to be a tightly packed collection of shipping around the submarine on fire. Wouldn't they be at fire or at least smoke risk? Perhaps authorities moved ships around the sub on fire to reduce the number of embarrassing photos?.
Reuters (carried in the SMH) reported April 8, 2015: "[Russian RIA] news agency reports said the fire [on the Oscar II class submarine Orel] had started near the stern during welding work that caused insulation materials to catch fire. RIA quoted a well-informed source as saying it was proving hard to put out the blaze because of thick smoke.
"At the moment they are 'attacking' with foam to try to put out the fire but it's not having any effect. Because of this they are considering whether to fully submerge the whole dock under water," the source said."
Note commentary of this Youtube includes "authorities accused of hiding information" in the past.
Although "80 firefighters and 20 fire trucks were involved in the work to extinguish the fire" Russian authorities claim after "preliminary inspections of the “Oryol”, no important infrastructure was damaged".
COMMENT
The Russian authorities are clearly taking pains to minimise the seriousness of the fire.
An alternate theory, to the fire starting with insulating material, is that the welding set fumes from the backup batteries alight. Even nuclear subs have batteries. Battery fumes are a more common cause of submarine fire than merely insulating material.
Pete