September 18, 2015

Dangerous Russian Nuclear Submarine Maintenance Standards

Readers may remember Submarine Matters’ article Russian Submarine Fire - Orel Perhaps a Write-Off? Of April 8, 2015. This was about a fire aboard the Orel (Oscar II class SSGN submarine, on April 8, 2015, which began during welding and cutting works. The fire started in the rubber insulation between the outer and the pressure hulls.

The main problem appears to be systemic - pockets of flammable gas from rubber, oil and grease  build up between the hulls – then the gas ignites on contact with a welder’s flame or sparks from hull cutters.

There was another similar but potentially catastrophic fire on a Delta IV SSBN, Ekaterinburg K-84 in dry dock in December 2011, as recounted below. 

On December 29, 2011 a Russian Delta IV SSBN (Ekaterinburg K-84 underwent unscheduled maintenance. The large hole was cut in Ekaterinburg's bow (apparently) before the fire. It is odd such a large hole was cut (perhaps over 3 meters across) - perhaps to replace torpedo tube gear, or the large bow sonar or to fix a distortion in hull steel? Cutting and/or welding this hole apparently started the fire. (This and other photos are in the Barents Observer, April 16, 2012).
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On December 29, 2011 Ekaterinburg K-84 on fire - which increased in intensity. Four torpedoes were in their tubes near the fire. More crucially 10 to 16 nuclear armed missiles (each with rocket fuel and 4 nuclear warheads) were also onboard behind the sail (Photo courtesy Barents Observer, January 3, 2012
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"....[on December 29, 2011] a fire broke out aboard Ekaterinburg [K-84], the second hull of the Delta IV class of SSBNs ...the submarine was undergoing dock repairs in a floating drydock...in the port of Roslyakovo (near Murmansk).  

Sparks from ongoing hull-cutting operations apparently ignited either oily residue or trash lubricants floating in the free-flood space between the outer and inner (pressure) hulls.  This space, which contains the submarine's cylindrical sonar array, is flooded when the submarine is afloat, but it is supposed to be drained when placed in drydock. 

In this instance, openings located under the sonar dome were welded shut, thus preventing the space from being fully drained.  The presence of water in the space should have been obvious to shipyard workers, especially given that the submarine was placed in the drydock three weeks earlier on December 8, 2011... 

About thirty minutes after the fire ignited, the rubber material within the free-flood space began to burn.  The flames then spread outside the space and onto the outer hull.  Subsequently the submarine’s anechoic tiles, which are made of rubber and used to reduce the amount of noise emanating from inside the submarine, began to burn, as did the adjacent wooden scaffolding... 

Adding to the seriousness of the accident is the fact that at least ten SS-N-23 Skiff ballistic missiles and four combat torpedoes were loaded aboard the submarine.  As this repair period was “unscheduled,” naval officials decided not to fully offload the submarine’s weapons. For “scheduled” repairs, all weapons are offloaded before repair work begins.  

The immediate danger of the fire was to the four torpedoes, which were amazingly still loaded into torpedo tubes that are located in a separate, confined space above the free-flood space containing the cylindrical sonar array.  Crew members were able to pull three torpedoes from their tubes, but the fourth torpedo was wedged inside the torpedo tube. [Russian fire crews would have been mindful of the explosion of torpedo fuel in the Kursk nuclear submarine submarine disaster in 2000]  News video from December 30 clearly shows water being sprayed directly into at least one of the starboard torpedo tubes.

By 3PM local on December 30, shipyard workers had flooded the drydock in order to lower the submarine into the water.  This allowed seawater to flood the free-flood space between the outer and inner hulls, thereby dousing all flames and rapidly lowering the temperature within the space.  Shortly afterwards, the fire was reported to be completely extinguished...

Now that most of Russia is enjoying a week-long New Year’s holiday break, investigators and military officials will be able to better craft a story for the public while simultaneously trying to figure out who’s to blame.  The more things change, the more they stay the same."

COMMENT

The main risk with Ekaterinburg K-84 was probably less a nuclear fission explosion but more the risk of torpedo fuel and torpedo warheads exploding. If that happened then further back rocket fuel exploding, blowing warheads out of the tubes and rupturing the submarine's two nuclear reactors would be catastrophic. The city of Murmansk, population around 300,000, and probably a much wider area would then have a major radiation problem.

The two events (Orel and Ekaterinburg) have much in common and point to a whole range of Russian submarine safety problems.

Pete

6 comments:

jbmoore said...

Well, they avoided something nearly as embarrassing as the Kursk incident.

John

Peter Coates said...

Hi JB

Yes an explosion of torpedo fuel (then warhead) on the Ekaterinaburg sub was probably narrowly averted.

A torpedo fuel fire on the Kursk led to a spread that sank the sub https://en.wikipedia.org/wiki/Kursk_submarine_disaster

"the crew of the Kursk was preparing to load a dummy 65-76 "Kit" torpedo when a faulty weld in the casing of the practice torpedo caused high-test peroxide (HTP) to leak, which caused the highly volatile kerosene fuel to explode."

"The Russian Navy did not recognise that the [Kursk] had sunk for more than six hours and because the emergency rescue buoy had been intentionally disabled, it took more than 16 hours for them to locate the sunken ship.

Over four days they used four different diving bells and submersibles to try to attach to the escape hatch without success. The navy's response was criticized as slow and inept.

The [Russian] government initially misled and manipulated the public and media about the timing of the accident, stating that communication had been established and that a rescue effort was under way, and refused help from other governments. The Russian Navy offered a variety of reasons for the sub's sinking, including blaming the accident on a collision with a NATO vessel. On the fifth day, the Russians accepted British and Norwegian offers of assistance." Too late.

Now I think Russia has some submarine rescue agreements with the West.

Regards

Pete

Nicky said...

HI Pete
At least they avoided another Kursk but I think it's endemic of their best practices and they need to modernize.

Peter Coates said...

Very true Nicky

The innate secrecy and probable technical conservatism of the Russian military should not hide safety breaches or poor standards. Too oftern this has endangered crews, Russian citizens even other countries on Russia's borders.

Regards

Pete

Anonymous said...

Hi Pete

I think they adopt vacuum double insulation structure and/or thermal insulation material for storage of liquid oxygen tank, but I do not think they use coolant.

Soryu carries amounts of hazardous materials fuel (kerosene, diesel oil), oxidizer (liquid oxygen), carbon dioxide absorbent (a small of amount of mono-ethanol amine and lithium hydroxide) and bomb. Reduction of amounts of hazardous materials and adoption of less hazardous alternative materials are required in submarine design in terms of occupational health and safety. In this meaning, abolishment of Stirling System which needs amounts of liquid oxygen and kerosene is in right direction.

Regards
S

Peter Coates said...

Hi S

Yes, there seems to be alot of combustable rubber (possibly giving of dangerous vapour) between Russian submarine hulls. Oxygen, kerosene and diesel leaking or properly stored may add to the fire hazards.

I do not know the extent mono-ethanol amine and lithium hydroxide are flamable. Is "bomb" mines or torpedo warheads?

Yes amounts of liquid oxygen and kerosene (for Stirling AIP and also other AIP technologies) sound dangerous.

I don't think any AIP equipped submarine has been tested in a war or had a major collision. AIP subs may prove too vulnerable in both situations.

Regards

Pete