快猫短视频

THE Soviet Union covered up two nuclear accidents that happened decades ago at an atomic bomb factory in Siberia, say Russian scientists who鈥檝e dated stray radioactive particles from a local river. By keeping the accidents secret the Soviets placed thousands of residents living downstream of the plant at risk from cancer. The radioactive contamination could still be a threat today.

Krasnoyarsk-26 was one of the Soviet Union鈥檚 three big secret atomic bomb complexes. Built inside a hill 50 kilometres north of Krasnoyarsk in the 1950s, the complex housed three reactors making plutonium.

Two reactors, closed down in 1992 and 1993, discharged their primary cooling water directly into the Yenisei river, which flows over 3000 kilometres north into the Kara Sea, then on into the Arctic Ocean.

Alexander Bolsunovsky from the Russian government鈥檚 Institute of Biophysics in Krasnoyarsk uncovered 11 of 12 鈥渉ot particles鈥� that turned up along the banks of the Yenisei between 1994 and 1999. These highly radioactive fragments of reactor fuel, containing isotopes of caesium, plutonium and strontium, were up to 330 kilometres away from the nuclear plant.

With the help of the Vernadsky Institute of Geochemistry and Analytical Chemistry in Moscow, Bolsunovsky has now estimated the age of the particles by analysing the ratio of two isotopes, caesium-137 and caesium-134, which decay at different set rates. He concludes that eight were formed around 30 years ago, and four around 20 years ago, suggesting they came from two separate leaks from the Krasnoyarsk reactors.

Levels of contamination in the past 30 years could have been high enough to cause the excess of cancers local doctors have picked up in riverside communities, Bolsunovsky told 快猫短视频. 鈥淭he residents of the nearby villages had no idea of the hazard and could have received enormous doses.鈥� The Soviet authorities kept the accidents a secret, he says.

Villagers still face a risk today. Spending a few hours within a metre of a particle could mean radiation doses in excess of the annual Russian safety limit of one millisievert.

The Russian Ministry of Atomic Energy has always denied that there have been any accidents at Krasnoyarsk-26, now known as Zheleznogorsk. But Murdoch Baxter, who used to head the International Atomic Energy Agency鈥檚 marine laboratory in Monaco, says Bolsunovsky鈥檚 evidence is convincing. 鈥淚n the past the Ministry has cast doubts on the quality and completeness of the early reported data on such particles. This paper is likely to dispel such doubts.鈥�