More Information On Russian Submarine FatalitiesFollowing up on WillyShake's report below:
Russian media sources are reporting that 20 sailors and shipyard workers were killed during "testing" after a "fire extinguishing system unexpectedly went off". From a BBC report on the incident:
Russian Pacific Fleet spokesman Igor Dygalo said both sailors and shipyard workers died in the incident, which occurred during sea trials.The first linked article says that the sub is "now moving to a temporary base. It is being escorted by an anti-submarine ship and a rescue vessel."
He said the submarine itself had not been damaged and there had been no radiation leaks...
...The submarine, whose name and class have not been revealed, has been ordered to suspend sea trials and return to port in the far eastern Primorye territory, Capt Dygalo said...
...There were 208 people on board at the time, 81 of whom were servicemen.
Twenty-one injured people have been evacuated from the submarine, sources at the fleet said.
Reports say the incident occurred in the nose of the vessel. The nuclear reactor, which is in the stern, was not affected.
The number of civilians on board indicates that the BBC report is correct that this seems to have happened during sea trials. I mentioned late last month that the Akula-II submarine RFS Nerpa, rumored to be heading to India on lease after shakedown, was out on sea trials. As I doubt that the Russians would have enough shipyard resources to have two boats out on sea trials in the Pacific simultaneously, I'd guess that this is the affected boat. This AFP article on the new incident reaches a similar conclusion.
Russian submarines operate with much smaller crews than American boats, so I would imagine that they rely more on automatic fire suppression systems than our boats do. (The Russians have lost at least one submarine to fire relatively recently, so I imagine they have a special interest in designing robust fire extinguishing systems.) Most naval fire suppression systems would probably use either CO2 or a Halon-like chemical, both of which would displace oxygen in the environment. While you have to take everything the Russians say with a grain of salt, I could imagine the fire suppression system emptying its contents into the torpedo room, and the inexperienced crew following their fire procedures and isolating all compartments; this could have resulted in the O2 concentration in the Torpedo Compartment dropping below that required to support life. If so, this is quite a tragic accident. Our thoughts are with the families and shipmates of the fallen mariners.
Update 1006 09 Nov: I'm updating this story over at The Stupid Shall Be Punished.