Chernobyl nuclear accident helped change world politics, professor says

Thursday, April 20, 2006

Calling it "the worst industrial accident in the history of the world," a University of North Texas engineering professor says the disaster at the Chernobyl Nuclear Power Station 20 years ago profoundly changed world politics.

The disaster occurred April 26, 1986 at a plant in Pripyat, Ukraine, which was then part of the Soviet Union. Because the plant had no containment building, a plume of radioactive fallout drifted over parts of the western Soviet Union, Eastern Europe, Scandinavia, the United Kingdom and the eastern United States. Large parts of the Ukraine, Belerus and Russia were badly contaminated.

Dr. Stathis Michaelides, the principal investigator for an international project on the "Transport of Radionuclides following the Chernobyl Accident" from 1993 to 1998, says the explosion at Chernobyl created the defining moment that led to the dissolution of the Soviet Union.

According to Michaelides, the explosion and the fire that burned for eight days made the 25-mile radius around the plant uninhabitable for more than a decade and set off radiation detectors across Europe, and as far away as Philadelphia.

"In the first 36 hours, the government of the Soviet Union denied that anything unusual had happened in its territory. Then when the repercussions of the disaster could not be contained, Soviet officials admitted to a minor accident, but refused all aid from the rest of the world," he says. "Eventually, however, they had to make a full acknowledgement of the catastrophe and reveal the causes of the accident to the world's scientific community."

In the disaster's aftermath, Soviet citizens realized "that the Soviet regime and its civil servants, in their desire to avoid scrutiny and criticism, mounted only poor efforts that failed to protect lives, livelihoods and the environment," he says.

Warsaw Pact nations realized that continued alliance with "a morally and financially bankrupt government" would lead to disaster for them at home, he says. In the years after the Chernobyl disaster, these countries began declaring their political independence, and in 1989, the Berlin Wall -- "the symbol of the Iron Curtain that divided Europe" -- fell, Michaelides says.

The environmental legacy of Chernobyl is still evident in parts of the Ukraine, Belarus and Russia, where several regions still have higher than normal concentrations of radioactive materials.

However, Michaelides says natural processes have proven to be a very resilient system in accommodating all the radionuclides that were dispersed during the accident.

"More than 80 percent of the radionuclides were deposited in the top soil in the vicinity of Chernobyl during the first week following the accident," he says. "Gradually, rainwater runoff washed out these radionuclides and carried them to streams, rivers and lakes. In this process, radioactive materials are bound to silt particles that are heavier than water and are deposited at the bottom of rivers and lakes where new silt and sediments have covered and partly buried them."

As a result, he says, radioactivity in the rivers of the region has dropped exponentially in the last 20 years and several cities in the region -- including Kiev, the capital of Ukraine -- have resumed using the water of the river Dnieper for their municipal water supply.

Michaelides adds the radioactive materials have continued to decay.

"The three most harmful nuclei -- Cesium-134, Cesium-137 and Strontiuim-90 -- have half-lives of approximately 30 years. This means that by 2016, only half of the original radioactive nuclei will remain," he says. "If they stay buried in the bottom of rivers and lakes they will not pose any threat to the environment."

He adds that although spring floods carry some of the radioactivity further downstream, "all scientific predictions agree that it will be several decades before the radionuclides will reach the Black Sea."

"By that time the decay will be high enough so that the last remnants of the Chernobyl catastrophe will not pose a real threat to the delicate sea environment," Michaelides says.

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