Thaindian News

Washington, Mar 18 (ANI): Neptunium, a waste product from uranium reactors, could pose a serious health risk should it ever seep its way into groundwater - even five million years after it is deposited at a dump.

Now, Danish researchers have found a naturally occurring substance called ‘green rust’ can help protect groundwater against radioactive contamination from stored reactor waste.

Bo C. Christiansen, a geochemist at the University of Copenhagen who specializes in ‘green rust’, describes how it contains neptunium.

For years, green rust was perceived as a problem. It was investigated primarily by material scientists who wanted to know how to avoid green rust formation in reinforced concrete.

However, a group of chemists, physicists, and geologists at the university’s Nano-Geoscience Research Group have been studying the substance’s beneficial properties in recent years.

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,” said Christiansen.

Green rust is a type of clay known 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.

Christiansen’s team conducted experiments demonstrating green rust’s ability to immobilize neptunium at the Swedish Nuclear Fuel and Waste Management’s pilot research facility at Okskarshamn on Sweden’s east coast and at the Karlsruhe Institute of Technology in Germany.

“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,” said Christiansen.

To ensure the security of radioactive waste, green rust could be established to surround the canisters.

“Green rust is no quick-fix to clean up after pollution that suddenly presents itself. But our experiments have shown the surprising result that nature can help to clean itself. Even when the pollution is with a substance as serious as neptunium,” said Christiansen.

The findings are published in the March issue of the journal Geochimica et Cosmochimica Acta. (ANI)