Much of this is in seven reactors from nuclear submarines and one ice-breaker vessel that were dropped into the sea with highly radioactive nuclear fuel inside them. Six of these fuel-laden reactors were dumped in shallow inlets of Novaya Zemlya between the Barents and Kara Seas, north-east of Murmansk.
Viktor Danelov Danilyan, the Russian environment minister, will today present a report outlining the enormity of the Soviet Union's illegal nuclear dumping to a meeting which is negotiating changes to the London Convention, a treaty that controls the marine dumping of nuclear and other wastes.
The report was written by a commission set up a year ago by Boris Yeltsin, the Russian president.
While most of the nuclear dumping occurred in the Sixties and Seventies, it continues today in violation of a London Convention international moratorium that began in 1983.
The report discloses that in 1989 the government of the Soviet Union, a party to the London Convention, told its fellow treaty nations that it 'has not dumped, is not dumping and does not plan to dump radioactive waste at sea'. But this was not true and the report says the Russian navy is still discharging low-level liquid radioactive waste. Last month, Japan protested after Greenpeace tracked a Russian tanker dumping into the Japan Sea.
The report also reveals acute problems in handling and storing the spent nuclear fuel and waste from Russian navy submarines. 'Existing temporary storage facilities . . . are overfilled, solid radioactive waste from vessels, ships and yards has been accumulating in containers in outdoor areas.' Given these problems, an end to dumping at sea becomes 'practically impossible', the report concludes. It would only lead to accumulation of waste onshore 'and cause a rise in social tensions and real threat to personnel and the population'.
The Russian commission estimated the total radioactivity associated with Soviet marine dumping is between 300 and 2,500 kiloCuries; the Chernobyl nuclear reactor explosion was responsible for the release of about 6,000 kiloCuries. The accidental loss at sea of three nuclear powered submarines added a further 650 kiloCuries.
The report says the greatest potential hazard to wildlife and humanity came from the dumping of reactors containing nuclear fuel in shallow Arctic waters. It also emphasises the many uncertainties; how long it would take before the reactor walls were breached by underwater corrosion, how far and fast the radioactive materials would be spread by currents once they escaped into the sea, how quickly they would enter and move up food chains.
Two joint research voyages by Russian and Norwegian scientists this year and last year have failed to find evidence that the dumped reactors and other wastes are contaminating the Barents and Kara Seas to date. Existing contamination levels were lower than in the North Sea, and could be explained by other factors including previous nuclear weapons tests, emissions from Britain's Sellafied nuclear reprocessing plant and Chernobyl fall-out.
The Russian Federation is expected to ask for help in investigating the scale of the environmental hazard and dealing with its naval radioactive wastes.