The
V.K. Komsomolets, a
Mike-class Soviet
nuclear Fast Attack submarine, was both a
prototype and (later) the only serving instance of its class. Although the West had thought its reactors were of some sort of exotic design (the most popular hypothesis was that they were
liquid metal cooled) they were in fact water-cooled like most others of their type. Due to her double titanium hull design, the boat was capable of reaching depths beyond 3,000 feet, more than three times the official '
test depth' of
steel-hulled submarines in U.S. Navy service. As
psy notes above, the ship ran into trouble on April 7th, 1989. The following is a brief description of the accident.
At approximately 1100 hours, the ship is underway at a depth of around 400 meters beneath the surface of the Norwegian Sea. The first incident in the disaster occurs in the aft-most compartment aboard - compartment 7. This space contains the steering mechanisms and several other auxiliary mechanical systems of the submarine, including high-pressure air pumps and access to the rear ballast and trim tanks. A high-pressure line leading from the air system to the ballast tanks ruptures due to a seal failure. A 'spray of oil' - likely hydraulic fluid - contacts a hot surface on some of the machinery and ignites. The control room, which has (seconds before) received an 'all clear' status report from compartment 7, remains unaware of the problem for several minutes. Eventually, a temperature alarm sounds for the compartment; when attempts to raise the sailors in that area are unsuccessful, the fire alarm is sounded.
At this point, Capt. Y.E. Vanin orders the submarine to head for the surface, and faces his first dilemma. The fire is spreading rapidly; the only procedure likely to halt it is to inject freon into the high-pressure system and flood the compartment, smothering the fire. However, this would also certainly suffocate any crewmen remaining in the compartment. Vanin delays as long as possible, then orders the freon dump. It is too late, however, as the high-pressure air has served as a blast furnace; the higher pressures in the compartment have forced vaporized oil and flame into the next compartment forward (compartment 6). Fire has arced through cable trunking into multiple areas.
As compartment 6 ignites, the turbogenerators (housed there) shut down. As a precaution, automatics disengage the propeller shaft from its electric drive, and breakers kick out to prevent the reactor from overheating due to the sudden drop in demand (and thus coolant flow). A reactor officer, seeing this, SCRAMs the reactor, shutting it down. The submarine begins to drift; with no forward way on, the dive planes cannot lift the boat. Immediately following, the sub loses hydraulic pressure and thus control of the planes. Capt. Vanin orders an emergency blow of all ballast tanks; this, coupled with a desperate emergency blow of the trim tanks, lifts the submarine to the surface. Vanin sends an encrypted message to North Fleet HQ informing them of his situation; the message is garbled in transmission.
The submarine is still on fire, with temperatures inside the titanium pressure hull reaching over 1,500 degrees Fahrenheit. According to survivors, the anechoic coating on the outside of the submarine's hull begins to melt and slough off in sheets. Vanin has ordered all crew not performing damage control outside to the deck to await rescue. Those within the hull don breathing masks to continue the fight. Unfortunately, the breathing air system has become severely contaminated with carbon monoxide from the fire, and they are forced to remove them. Less than an hour after the first incident, the fire has spread throughout the submarine. The Engineer and others use self-contained breathing apparatus to check the reactor compartment, where the last nine men had been stationed; two are still alive, and are evacuated to the deck. Further forward, a seaman manages to start an emergency Diesel generator before succumbing to smoke; he is evacuated and his post assumed by an officer.
Meanwhile, around 11:41 am, Vanin's messages finally get through to North Fleet. They are garbled. North Fleet does, however, immediately alert sea-search aircraft and crews, instructing them to prepare to look for a Soviet submarine in distress. By 12:45, Vanin has abandoned procedure and is broadcasting in the clear. With this confirmation, the aircraft are dispatched and North Fleet lurches into crisis mode. By 2:20, search aircraft (not amphibious) spot the stricken boat. Their appearance cheers the crew, who take this to mean rescue is imminent. Although the interior of the sub is not habitable, with six-inch visibility and lethal fumes and scattered fires, the hull maintains integrity, and most of the crew is on deck. By 4pm, however, the sea state has worsened, as has the situation. Capt. Vanin and his officers, still within the submarine, have been attempting to right the boat from a list developed on surfacing. With little information, Vanin orders several trim tanks flooded in an attempt to 'roll' the boat; however, the stern settles from the weight and brings hot sections of the hull in contact with the water. The pressure hull ruptures, and the boat begins to settle at the stern.
Capt. Vanin orders the crew to abandon ship, and returns below to retrieve the officers still below deck. Life rafts are broken out and a few are dropped from the circling aircraft, as crewmen begin to leave the submarine's deck. As the boat is sinking, the captain has the hatch shut behind him to avoid flooding, with the intention of using the submarine's escape pod once he retrieves the crew. They crowd the pod; one of their number doesn't make it, and the pod 'hangs up' for a few minutes. It finally breaks free at perhaps 1,000 meters, and rises swiftly to the surface. The pressure imbalance blows the hatch off the pod as it broaches, and it quickly floods. Only one officer makes it out of the pod before it sinks, taking the Captain and crew down with it.
The frigid waters kill several more crewmen before a Norwegian fishing boat arrives and takes on 30 survivors, a few of whom will later die due to smoke inhalation and toxic fume poisoning/lung damage.
The second part of the Komsomolets' story begins here. The ship sank in approximately 2,000 meters of water. The Norwegians had been closely monitoring the situation, especially when informed that the drama unfolding was not a drill. The disaster and subsequent coverup of Chernobyl are still fresh in the minds of the USSR's western neighbors; they are acutely aware of the dangers of radioactive contamination. The Komsomolets sank in an area which was thought to have deep-sea currents, which could spread the ship's reactor fuel across the sea floor and into the ecosystem.
The Red Fleet research ship Keldysh, using its two deep-diving submersibles, located the Komsomolets 2,000 meters down a couple of months after the sinking. Performing an initial survey, the Soviet Union pronounced the area safe. The accusations continued to fly, however, and the Keldysh revisited the site in 1991. The sub was found to have settled, exposing the bow area. Russia admitted that the boat had several torpedoes aboard with nuclear warheads. While the reactor core was not likely to pose a severe problem since the containment vessel (while no longer watertight) remained essentially intact, the hull of the submarine was corroding quite rapidly due to a reaction between the titanium of its pressure hull and the steel and aluminum of the remainder. The torpedo warheads were of much lighter construction than the reactor vessel, and proved impossible to retrieve as they were wedged into their loading tubes. Nightmare scenarios of plutonium 'flaking' off the weapons, coupling with titanium dust and spreading across the sea floor were feared.
Russia had taken the position that the dangers posed by the wreck were minimal. Samples taken during the 1991 and 1992 multinational survey expeditions had shown that the radiation levels around the wreck were quite low, within 'drinking water regulation levels' according to the Russian and Norwegian surveyors. However, between the 1992 and 1993 surveys, increasingly grim reports began to circulate from Russia about the dangers of the wreck, which suddenly appeared to have grown dramatically. Despite this, the 1993 survey found radiation still quite low; however, a couple of worrisome facts emerged along with some reassuring ones. The reactor had begun slowly leaking cesium-137 into the waters, albeit at very low levels; and newly-discovered damage to the forward torpedo room (in the form of a 20-foot hole blown in the hull from some sort of internal explosion) meant that not only had the nuclear torpedoes been subject to severe shocks, but were even less retrievable. The submarine itself was too badly corroded and damaged to attempt to raise it; any such attempt would have broken the hull into multiple pieces, spreading contamination further. Additionally, any attempt to move the reactor vessel could have conceivably disturbed the moderator rods, causing the reactor to 'restart' spontaneously during the operation. On the bright side, the currents in the area were shown to have very little vertical motion or mixing, and the currents at the bottom were slowly moving northward away from Europe and her fishing areas.
The 1993 survey also located the escape capsule. Recovery was attempted (in the hopes of retrieving logs and records) but failed when a cable snapped, allowing the capsule to sink back to the bottom. Following this survey, the Russian authorities decided that the submarine posed a future contamination danger, and announced their intention to 'entomb' the bow of the boat using a special chitinous compound they were developing for the task. In 1994, press releases announced that the operation had been carried out, and that the Komsomolets was covered in containment material. The submarine is being slowly covered by silt and mud. One of the only artifacts retrieved was the ship's clock, which rests in the Russian Naval Museum in Leningrad, its hands frozen at 5:43pm, 7 April 1989.
Sources: