Russia has a nuclear-powered research submarine nicknamed Losharik (Project 210 Project 10831, Лошарик). The NATO designation is AC-12. From what I've read about her, she is a deep-diving, small craft. Her mission is probably similar to that of the US Navy's NR-1 submersible, and thus her missions would tend to be very secretive.
I'm not even certain this is the same ship - Google Images isn't always right. The sail looks quite a bit different from the ship in the previous image.
Below is a rendering of the profile of this ship. It appears to have skids so that it can settle on the ocean floor, as well as a manipulator arm. There also appear to be vented ducts, allowing the ship to pivot and adjust depth while at zero speed. Photo courtesy
Below: I don't read Russian, but it's clear that this ship has quite a few accessories along the keel that most submarines are not equipped with. The yellow silhouettes are comparing the relative size of a Project 667BDR (Delta III ballistic missile submarine) to the smaller Losharik. Looking at the cutaway of Losharik, I see six interconnected spherical compartments. Four of these appear to be living spaces (control, sonar, berthing, radio, etc). One spherical compartment is for the reactor, and one is for the propulsion machinery - turbines, generators, reduction gears, etc. The spherical shape of the compartments would lend credibility to the reports that this is a deep-diving ship.
On July 1, 2019 Losharik experienced a main storage battery fire, which sadly killed fourteen crew members. The crew size is estimated to be just 25 men, so it's possible that more than half the crew perished in this accident.
Battery fires occur from time to time on submarines. Submarine batteries are enormous, and contain thousands of amp-hours of energy. When they catch fire, things get nasty. Unlike other electrical circuits, it's not possible to de-energize the main storage battery. You can disconnect from the battery, but the voltage and the energy remain - so if the battery itself is electrically compromised, there's no stopping the fireworks.
Below: Cutaway of a WWII era submarine, showing the size of the two main storage batteries (modern subs have only one). Each cell is 4-1/2 feet tall, and generates 2.2 volts. Counting the cells in this image reveals six banks of 21 cells for a total of 126 cells. Each 2.2 volt cell is connected in series with the others, to give a combined output voltage of about 280 volts DC.
There are a number of mechanisms that can start a fire in the main storage battery:
When seawater comes into contact with the battery electrolyte, you get an exothermic (generates heat) reaction, which also releases gaseous hydrochloric acid. Sea water is of course also highly conductive, and has caused electrical shorts and fires in that manner as well.
Hydrogen fires are possible if the battery is not properly ventilated - particularly during charging.
Lastly, individual cells of the battery can shift. Submarines tend to roll quite a bit when surfaced due to their round bottom, and they frequently make steep diving and surfacing maneuvers for training. Battery cells have been known to shift with respect to each other at sea, causing electrical connections to loosen and develop an electrical resistance.
Electrical resistances don't have to be very large to cause serious problems. When the reactor is down or when the turbine generators are offline there are massive electric current outflows from the battery. When that happens, a very minor electrical resistance may be carrying a couple thousand amps of current, and even minor electrical resistance will generate a lot of heat. As the connection heats, this increases resistance further, and very quickly the bad connection melts and/or catches fire.
Below, an infrared (heat) image of a couple of loose connections in a small power distribution panel.
(image courtesy of Infrared Consultant Group)
Regardless of the source or cause of a fire, they have one thing in common on a submarine. When a major fire breaks out, it will rapidly consume the available oxygen. Very quickly, the air will be thick with hazardous fumes, and there will be so little oxygen remaining that the air will no longer support life. On a submarine, there is no escape. You can't run up top-side, jump overboard, or even call for help. You have to attack the fire, surface the vessel, ventilate the ship, and then call for assistance - and hope that someone is nearby. All of these actions take time, because submarines typically don't operate near the surface.
In the interim, the crew fight the fire, because the Fire Department doesn't respond to emergencies that happen deep underwater. The crew must breathe with re-breathers, SCBA type devices, or plug-in breathing devices, while controlling the ship and dealing with the situation. It's critical for each crew member to keep their shit together under some incredibly stressful conditions. There is no mission control or flight tower to assist in casualties. There won't be any radio communication unless you are able to reach the surface, and nobody even knows where you are.
I found it a bit surprising that so many of the crew died. Breathing devices should have been available, and the crew should have been repeatedly trained to use them until they could do it in their sleep. Then again, sometimes situations arise that are impossible to survive - and this was probably one of them. I'm interested in learning a little more about what happened, and hopefully we will get that information.
In any event, it's a terrible situation to die in, and I'm always saddened when submariners are killed.
UPDATE 1:
The most recent article I've read on this is from Ars Technica. The author goes a bit further afield than I am willing to comment about regarding the military and political aspirations of a sovereign nation.
On the "Technica" side, the article suggests that Losharik was stricken by a hydrogen explosion and fire in the battery compartment. The article states that the crew's emergency air supplies would only last 15 minutes. The ship made an emergency surface, but not before 14 men perished. Presumably those who were lost had been engaged with fighting the fire.
UPDATE 2:
Losharik was using Lithium Ion cells for the main storage battery. It had initially been outfitted with silver oxide cells, but due to worsening of Russia-Ukraine relations, the silver oxide cells were replaced with Lithium Ion cells. This type of batteries have their quirks, notably a tendency to become very hot on discharge, and to have runaway current (which also generates heat) on charge.
1 comment:
And to think everyone, at least in our Navy, volunteers for such duty. You all should be paid a salary equal to a bank CEO for such work. I'm hoping your mother wasn't privy to all this information while you were serving. You also have my gratitude for your service. I also enjoy reading about it, but for the losses.
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