The Mineralogy of Nuclear Meltdowns
|Starts:||13:00 22 May 2019|
|Ends:||14:00 22 May 2019|
|What is it:||Seminar|
|Organiser:||Department of Earth and Environmental Sciences|
|Who is it for:||University staff, External researchers, Adults, Alumni, Current University students, General public|
|Speaker:||Claire Corkhill, Dept. Materials Science and Engineering, University of Sheffield|
In April 1986, Reactor 4 of the Chernobyl nuclear power plant underwent a catastrophic failure. This nuclear incident resulted in 31 direct deaths and caused a radioactive plume to spread across much of Europe and the former USSR. During the meltdown of the reactor core, temperatures reached >1600°C from the uncontrolled decay heat of the fission products, causing the nuclear fuel and zirconium cladding to melt together. More than 100 tons of molten reactor core magma moved through the sub-reactor rooms, incorporating structural building materials such as steel, concrete and sand. The minerals that formed, known as lava-like fuel containing materials (LFCM), are highly crystalline, radioactive, glass-like slags.
25 years later, in 2011, an earthquake off the eastern coast of Japan resulted in a loss of coolant accident at the Fukushima Daiichi Nuclear Power Plant. After the partial meltdown of Reactor Units 1 to 3, at temperatures in excess of 2000°C, UO2 fuel pellets reacted with zircaloy fuel cladding. Since it has not yet been possible to retrieve any of the materials from within the reactor buildings, due to the extreme levels of radioactivity, the precise mineralogical details of the melted core are not known. However, it is thought that a mineral phase with a composition of U1-xZrxO2 was formed, containing a variety of fission products and minor actinides, and it is possible that glassy lava-like minerals are also present.
The removal of these materials from the reactors and the sub-reactor buildings is vital to the remediation of the sites. This is a critical step on the pathway to allowing re-habitation of the local areas, which can only be completed once a thorough understanding of the composition and microstructure of the lavas has been accomplished. This talk describes the research being performed at the University of Sheffield, with our collaborators in the UK, Ukraine and Japan, to understand these fascinating nuclear meltdown minerals.
Claire Corkhill, Dept. Materials Science and Engineering, University of Sheffield
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