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The Russian nuclear-powered submarine, the Kursk, still lies at the bottom of the Barents Sea off the Norwegian coast.
The Russians claimed that the reactor was shut down and denied that the Kursk has any of its nuclear cruise missiles on board although CND is always sceptical of any statement about nuclear weapons, from any nuclear-armed state.
John Ainslie, Scottish CND Administrator, says the latest accounts of the submarine accident on the Kursk are very worrying and do not accord with earlier statements and assurances.
The US has said that there was one explosion followed very shortly by a second larger explosion. Accounts of the state of the submarine say there is extensive damage from the bow to under the control tower.
This suggests that one torpedo exploded and set off a massive explosion of several torpedoes within the bow compartment. This external damage would have been sufficient to sink the vessel. It probably will have caused far more damage within the pressure hull. Most of the blast will have gone backwards, probably completely wrecking the control room, making it impossible to send out any messages saying the reactor was shut down.
It is also possible that the blast could have damaged the reactor area and triggered fires in the aft of the Kursk. The reactor may well have shut down automatically but secondary events triggered by a huge blast at the bow may have made it very difficult for any reactor controls in the aft to be operated.
CND is in full agreement with Alexander Pikayev who write in today's International Herald Tribune that the Europe should do more to help finance Russian nuclear disarmament in general and the decommissioning and dismantling of all Russia's nuclear submarines.
For further information and comment contact John Ainslie on 0141 423 1222 or CND Press Officer Nigel Chamberlain on 020 7700 2350
See a fuller report at http://www.cndscot.dial.pipex.com/news/000817a.html
The following is an initial assessment of the radiation risks arising from the loss of the Russian submarine Kursk and general issues about explosive hazards on nuclear submarines.
Radiation hazard from Kursk
According to the Norway based group Bellona the Oscar II class has two OK-650 b reactors each of which produces 50,000 shaft horsepower. The power output of each reactor is given as 190 MW. So the total output from the reactors on the submarine would be 380 MW.
This can be compared with estimates for a British Trafalgar class submarine. These produce 15,000 shaft horsepower. The power output from the single reactor is estimated to be around 70 MW.
The significant difference can be related to the relative size of the vessels. The Oscar II class has a beam of 18 metres and a draft of 9 metres. Whereas the Trafalgar class have a beam of 9.6 metres and a draft of 8 metres. With a much larger size substantially more power is needed to propel the Russian submarine at speed through the water.
Amount of Uranium
The fuel core in a Trafalgar class submarines may contain around 220 kg of Uranium. Each reactor on Kursk is likely to contain around 600 kg of Uranium. So there will be around 1.2 tonnes on the submarine. Calculations John Large has made for the Komsomolets suggest the amount of Uranium may as great as 3 tonnes. As the level of enrichment is probably lower than on British submarines the total mass of the fuel core will be greater. Uranium 235 has a half life of 710 million years.
Radioactive Inventory
One MoD document gives a standard Trafalgar core inventory of 440,000 TBq. Other estimates are higher. Given that the estimated power output of Kursk s 5 times greater the core inventory is likely to be at least 2,200,000 TBq. Comparison with Chernobyl
These figures are equivalent to between 0.6 and 3 percent of the inventory of the Chernobyl reactor. However in the case of Chernobyl it is possible to build structures around the reactor.
Immediate Risk
When a submarine reactor is shut down there is still a significant amount of heat produced in the reactor by radioactive decay. For this reason there has to normally be a supply of electricity to power the cooling pumps. This will remain a problem for several weeks.
Long Term Risk
Over time the metalwork which contains the radioactive material will decay allowing it to be released into the sea. The radioactive inventory will by then have decreased, but will still be substantial.
State of the reactor on Kursk
While it is accepted that the reactor on Kursk has been shut down the circumstances of the shut down are not known.The explosion may have had an effect on reactor operations in the initial seconds and minutes of the accident.
Explosive hazards on submarines
Kursk has two hulls which are designed to withstand an impact from an average torpedo. If it was sunk by an explosion in the torpedo compartment then it was probably a very large explosion. The detonation of one torpedo could have triggered the detonation of others. This point was made in the official inquiry into the loss of the USS Scorpion.
Nuclear powered submarines carry a dangerous cocktail of explosives and nuclear material. No high explosives would ever be permitted next to a civil reactor. While the problems are particularly acute with the Russian Navy the danger is inherent in all military nuclear powered vessels. The Spearfish torpedoes carried on British submarines today are a particular problem because of the large explosive power in the warheads and the toxic and explosive hazards of the Otto fuel which propels them. Two workers were killed during early experiments with this fuel. A Trident submarine carries 700 tonnes of high explosive in the form of solid fuel in the rockets.
Explosions on submarines
HMS Sidon June 1955 The diesel powered British submarine sank following a torpedo explosion in Portland harbour.
K-129 8 March 1968 Explosion on this Russian diesel powered nuclear armed submarine in the Pacific resulted in the vessel sinking. Reported to have been raised by the US Navy in 1974.
USS Scorpion 22 May 1968 Nuclear powered US submarine. The official inquiry into the sinking implied that it must have jettisoned a torpedo which then turned and sank the vessel. The alternative of an explosion in the torpedo compartment was examined but considered less likely.
K-219 Yankee class 6 October 1986 Explosion in the missile launch tube of this Russian nuclear powered submarine. The vessel then surfaced. A second fire affected the reactor. Most of the crew were evacuated. 4 lives were lost.
Typhoon class October 1991 Explosion of a ballistic missile in the launch tube of a Russian Typhoon class in the Norwegian sea. Returned to port.
Rubis class 30 March 1994 Explosion in the steam system on French nuclear powered submarine 45 miles from Toulon. 10 died.
Nuclear submarines on the seabed
USS Thresher 10 April 1963 The Thresher was on deep diving trials when the reactor shut down. Attempt to blow the tanks failed and the submarine sank 100 miles east of New England. The submarine is in six sections on the seabed. Depth 2590 m. All 139 onboard died. Cobalt 60 from the reactor was detected in the sediment. 1 nuclear reactor onboard.
USS Scorpion 22 May 1968 Details above. 2 nuclear weapons and 1 reactor onboard.
K-8 November class 8 April 1970 Fires on this Russian nuclear submarine resulted in a reactor shut down. The vessel surfaced but auxiliary power supplies could not be started. Some of the crew were evacuated. On 11 April control of the vessel was lost and it sank in the Bay of Biscay. 52 died. Depth 4000 m. 2 nuclear reactors
K-219 Yankee class 6 October 1986 Details above. Near Bermuda. Depth 5500. 34 nuclear weapons and 2 reactors onboard.
K-278 Komsomolets. 7 April 1989 There was a fire on this Russian nuclear powered submarine and the vessel surfaced then lost power. Some of the crew were evacuated but 41 lives were lost when it sank near Norway. Depth 1685 m. 2 nuclear weapons and 1 reactor onboard.
Sources:
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