Radioactive waste decaying down at the dump needs millions of years to stabilize. The element Neptunium, a waste product from uranium reactors, could pose an especially serious health risk should it ever seep its way into groundwater even 5 million years after its deposition. Now, researchers at the University of Copenhagen have shown the hazardous waste can be captured and contained. The means? A particular kind of green goop that occurs naturally in oxygen-poor water.
Bo C. Christiansen is a geochemist at the University of Copenhagen who specializes in "green rust". In a recent article published in the prestigious journal Geochimica et Cosmochimica Acta, Christiansen describes how green rust is able to, so to say, encapsulate and contain neptunium. It's an insight that can greatly influence how and where to dispose of radioactive waste.
"Our study shows that even the safest encapsulation of radioactive waste could be made safer if radioactive waste canisters are buried in a place where green rust will form," explains Christiansen.
For years green rust was perceived as a problem. The substance was investigated primarily by material scientists who wanted to know how to avoid green rust formation in reinforced concrete. In recent years however, a group of chemists, physicists and geologists at the Department of Chemistry's Nano-Geoscience Research Group have been studying the substance's beneficial properties. The results have exceeded all expectations.
"Neptunium is a relatively exotic problem. Not a lot of people need to safeguard a radioactive waste depot. But green rust appears to be effective against nearly any kind of pollution," says Bo Christiansen.
Green rust is a type of clay referred to as an anionic clay. Because it consists of iron which has not entirely rusted, green rust has an electron deficit. This makes it react very readily with other pollutants, some of which are quite prevalent.
|Contact: Jes Andersen|
University of Copenhagen