The Nuclear Hazards of the Recovery of the Nuclear Powered Submarine Kursk

THE NUCLEAR HAZARDS OF THE RECOVERY OF THE NUCLEAR POWERED SUBMARINE KURSK Peter Davidson Principal Safety Consultant, NNC Ltd Huw Jones Commander, Royal Navy John H. Large Large & Associates, Consulting Engineers

THE FOUNDERING OF THE KURSK

On Saturday, 12 August 2000 and exactly at 7.29.50 GMT a small and relatively insignificant seismic disturbance was recorded by a Norwegian seismological station. It was followed one hundred and thirty five seconds later with a much more significant event, equivalent to about 3 to 3.5 Richter scale. None of those at the recording stations in Norway, Finland, Scotland, Canada, Alaska and elsewhere realized that this second explosion marked the death knell of an advanced nuclear powered submarine in the Barents Sea.

During the morning of 14 August the rescue centre at Bodø in northern Norway received rumor of an accident on board a then unknown Russian submarine somewhere north of Murmansk. This was the first inkling in the West of a very serious situation, the details of which were to unfurl over the following hours when it became apparent, and was subsequently confirmed by the Russian Federation (RF) Northern Fleet headquarters in Severomorsk, that a submarine had foundered. At about 16.30 that day the Norwegian Moscow embassy was notified by the Russian Federation authorities that there had been an accident to a submarine — that boat was the OSCAR II (RF PLARK class), cruise missile armed and nuclear powered submarine Kursk.

It is now known that Kursk left her home base in the Uraguba bay on 10 August, with a total complement of 118 men aboard, two of whom were torpedo designers. She was heading out to participate in sea exercises east of the Rybatschi Peninsula about 200km north of Murmansk. Kursk was assigned to an area of the sea cleared as a torpedo range under the supervision of the battle group command cruiser Pyotr Veliky, where she was to test fire two unarmed, prototype torpedoes from the forward port 650mm diameter tube that had been specially adapted for the trials.

It was the second firing that went so wrong. Speculation is, and it can only be speculation because the damage to the forward compartments was so great, that the gas generating system of the second prototype torpedo reacted with its main propellant, burning and exploding with an equivalent power to that of 100 to 200kg of TNT.

The prototype torpedoes were of the super cavitating type. This type of deep diving, high-speed torpedo envelops itself in a gas envelope generated at its bow with, essentially, the gas being replenished at the same rate as its progress through the water. The gas generating agent was hydrogen peroxide and, probably, the second prototype torpedo that initiated the sinking was an antisubmarine weapon (ASW) being deep diving and powered by a lithium-fluoride internal propulsion system.

The damage sustained from this first explosion, which alone the Kursk could have withstood, can be pieced together from the first of the two seabed debris fields. The debris included plates from the outer (flood) casing and, significantly, components of the port hydroplane hydraulic mechanism and the forward ballast and trim tanks. At the time of the first explosion, Kursk was positioned for torpedo firing, at periscope depth in the sub surface layer where to assist with depth control and, to avoid porpoising, she would have been trimmed to negative buoyancy, maintaining her sea depth by driving hydrodynamically against her forward planes at up to about 6 knots.

The centre of the first explosion seems to have been ahead of the foremost section of the pressure hull suggesting that the torpedo was loaded into the firing tube so, if the inner torpedo hatch was and remained closed, the damage to the bow compartment would have been minimal. However, the sonar trace taken by the nearby RF cruiser Pyotr Veliky shows continuing activity following the initial explosion spike, which could be interpreted as severe burning and jetting of the torpedo propellant system into the weapon stowage compartment (Compartment № 1).