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New Theory Sheds Light on How the Chernobyl Disaster Began

Wendelin Jacober/Flickr

Swedish researchers questioned the original theory of Chernobyl's meltdown and present new data challenging that theory.

A new study released by Swedish researchers has called into question what scientists think they know about the origin of the Chernobyl disaster - the most catastrophic nuclear accident in history. Traditional thought indicates a power surge caused massive steam explosions, which in turn spewed radioactive debris into the atmosphere. But now that story is being challenged.

They hypothesize that the first explosive event was a jet of debris ejected to very high altitudes by a series of nuclear explosions within the reactor. This was followed, within three seconds, by a steam explosion which ruptured the reactor and sent further debris into the atmosphere at lower altitudes.

Researchers from the Swedish Defense Research Agency, Swedish Meteorological and Hydrological Institute, and Stockholm University have based their speculation on new analysis of xenon isotopes detected by scientists four days after the incident at a city far from the primary track of Chernobyl debris.

These isotopes were the product of recent nuclear fission, suggesting they could be the result of a recent nuclear explosion. In contrast, the main Chernobyl debris which tracked northwest to Scandinavia contained equilibrium xenon isotopes from the reactor's core.

Analyzed together with weather patterns, damage at the reactor site, and eye witness testimony, the scientists are confident in this new theory. Said lead author Lars-Erik De Geer,

"We believe that thermal neutron mediated nuclear explosions at the bottom of a number of fuel channels in the reactor caused a jet of debris to shoot upwards through the refuelling tubes. This jet then rammed the tubes' 350kg plugs, continued through the roof and travelled into the atmosphere to altitudes of 2.5-3km where the weather conditions provided a route to Cherepovets. The steam explosion which ruptured the reactor vessel occurred some 2.7 seconds later."