[Nuclear Chemistry] Elephant's Foot

Chernobyl, a once active nuclear power plant, underwent a serious disaster 1986 when an emergency shutdown due to an unexpected power surge failed, leaving the reactors without a proper cooling system. The water that usually runs through the reactor’s core to cool it quickly vaporized. The vaporization of the water increased the pressure, causing several steam explosions in the plant. The explosions due to the steam destroyed the lead and steel that usually insulate the reactor’s core, causing it to overheat and melt. This oozed out of the reactor much like lava. Weeks later, as the workers made their way through the facility, they discovered what is now known as the elephant’s foot, mainly for its wrinkled look, in one of the sublevel after it had melted through the floor above. This substance (a mixture of the reactor’s core, concrete, sand, and control rods) is called corium, one of the most toxic substances known that has only been created a total of five times, this being the largest amount. As the workers neared the foot, the radiation sensors they used read around 10,000 roentgens (8770 rads -- 1000x stronger than the amount of radiation linked to an increased risk of cancer), so in order for them to get a picture they had to push a camera around the corner to take it (they were unable to use electronics because of the radiation). However, because of the mass amounts of radiation being given off, all pictures taken come out much more grainy than what might be expected. The most famous picture with the Elephant’s foot was taken by Artur Korneyev, who took a selfie of sorts with it. Although it is most likely no longer undergoing active fission, the foot, at one time, released a combination of alpha and gamma particles due to the Uranium in it.

Sources

http://nautil.us/blog/chernobyls-hot-mess-the-elephants-foot-is-still-lethal

http://rarehistoricalphotos.com/the-elephant-foot-of-the-chernobyl-disaster-1986/

https://en.wikipedia.org/wiki/Corium_(nuclear_reactor)