![]() ![]() The result was small-scale batches of materials that exhibit the same uranium, zirconium and trace metal phases as LFCMs recovered from Chernobyl. To do so, they mixed precise amounts of reagents containing elements known to be present in real LFCMs and heated them under a reducing atmosphere at 1500˚C for four hours, then at 720˚C for a further three days. Now, a team from the University of Sheffield has used depleted uranium to develop low-activity materials that accurately mimic the microstructure and mineralogy of real-LFCMs. Past research has involved chipping off small quantities of material and handling them using protective equipment, but such studies have been limited by the risks posed by the material. Studying real LFCMs is very challenging, however. It’s estimated that the LFCMs at Chernobyl are releasing up to 10kg of dust each year. The water has caused new, uranium-containing phases to build up on the surface of the material and, when the humidity in the sarcophagus drops below 85%, a significant amount of radioactive dust forms. Alongside concerns about groundwater contamination, one area of interest relates to corrosion damage caused by water condensation that has collected inside Chernobyl’s sarcophagus. The elephant’s foot’s radioactivity, and that of other lava-like fuel-containing materials (LFCMs) at Chernobyl, has declined significantly since 1986, but it is still dangerous to approach it. The mass was so radioactive when it first formed that if you had stood beside it, it would have killed you in around 300 seconds. Despite being only a small part of the roughly 100 tons of lava created during the meltdown, the elephant’s foot has become symbolic of the horrifying legacy of Chernobyl, largely due to its intense radioactivity. It wasn’t until December 1986 that members of the clean-up crew discovered an off-shoot of the radioactive mass that has subsequently come to be called the elephant’s foot. Over time, the lava melted through the base of the reactor vessel and several floors of the building before eventually coming to rest in the basement where it cooled and solidified. The vessel was so hot that that the zirconium cladding separating the fuel from the coolant fluid began to melt and combine with the uranium, steel, concrete and sand present to form a radioactive, glass-like lava. When reactor 4 at the Chernobyl nuclear power plant suffered a catastrophic meltdown on 26 April 1986, the uranium core reached temperatures in excess of 1600˚C. ![]() The simulant materials offer a much safer way of studying radioactive molten waste such as the infamous ‘ elephant’s foot’ at Chernobyl as they are only slightly radioactive. The mass formed during the reactor meltdown as a searingly hot lava of uranium and reactor material burnt its way through several floors into the basement of the power plantĪ new class of material has been created in the lab that mimics the radioactive, lava-like waste created during nuclear meltdowns like those of Chernobyl and Fukushima. The ‘elephant’s foot’ at Chernobyl nuclear power station. Source: © Universal History Archive/Universal Images Group/Getty Images ![]()
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