However, the Chernobyl melt contained little or no water. Credit: Denis Fougerouse, Author provided Until now, these features were attributed to the action of water dissolving the mineral.Ī zircon crystal from the Chernobyl melt shows surprising ‘re-equilibration textures’ that geologists had previously assumed were created by contact with water. Surprisingly, the zircons from Chernobyl displayed features called "re-equilibration textures", which are also found in many natural zircons. On the contrary, zircons from natural rocks have long, convoluted histories that are hard to untangle. In many ways they can be considered analogous to controlled experiments, but from an extremely dangerous setting that cannot be reproduced safely in a laboratory environment. Zircons sampled from the solidified corium at Chernobyl are special because we know a lot about the conditions in which they formed and their history. It is also very resilient to harsh geological conditions and is stable for billions of years. Geologists and Earth scientists love zircon, because studying it can reveal the age when rocks formed and what geological process formed them. Zirconium, silicon and oxygen: all the ingredients were present in the Chernobyl melt to crystallize zircons (ZrSiO₄) about the width of a human hair. Corium dissolved sand and concrete, which have a high silicon composition. Uranium fuel rods are made of enriched uranium oxide, clad in zirconium alloy. It can dissolve steel, sand and concrete, and it transforms water into radioactive steam almost instantly. For comparison, the temperature of natural lava from volcanoes ranges from 500 to 1,000℃.Ĭorium is so hot, it eats everything in its way. The corium at Chernobyl reached 2,600℃, almost twice as hot as the surface temperature of the space shuttle during atmosphere re-entry or half the temperature at the surface of the sun. Corium is extremely hot and generates its own heat from radioactivity. Nearby radiation exposure to corium can kill within minutes, but that is not all. Molten reactor material is called corium, and it's a serious contender for the most dangerous substance on Earth. In new research published in American Mineralogist, my colleagues and I show tiny zircons formed at Chernobyl change our understanding of how these crystals behave-and what they tell us about Earth's past. This hellish molten soup has proved an unexpected source of insight for geologists like me. The melted fuel rods pooled temporarily at the bottom of the reactor chamber before making their way into the deeper levels of the power plant. It was the worst nuclear disaster in history, releasing more than 400 times as much radioactive material as the Hiroshima atomic bomb.Īn uncontrollable chain reaction inside the reactor caused a sharp increase in temperature that ultimately resulted in the fusion of the fuel rods, a steam explosion and a fire. The Chernobyl nuclear accident was caused by an unfortunate cocktail of human error and flawed reactor design.
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