New material to dispose off nuclear waste found

WASHINGTON, AUGUST 4: A new, crystalline material that can withstand pounding radiation might provide a safer grave for high-level nuclear...

WASHINGTON, AUGUST 4: A new, crystalline material that can withstand pounding radiation might provide a safer grave for high-level nuclear waste, an international team of scientists said on Thursday.

The scientists hope they can fine-tune the material into a form that can be used to contain waste safely for tens of thousands of years. quot;If this work points towards the way to finding the absolute best radiation-tolerant material, and it is then used as an encapsulation material, then this is phenomenally important,quot; said Robin Grimes of London8217;s Imperial College of Science, Technology and Medicine, who worked on the study.

The secret of the material, called erbium zirconate, is its ability to put up with a little disorder, Grimes said. Currently, high-level nuclear waste such as spent fuel from nuclear reactors is stored in containers that may last for only about 100 years.

These are put into geologically stable places such as disused salt mines, or buried very deep in the earth, but if the containers rupture, the radiation could escape into the environment.

The materials currently used in containers are glass-like chemicals. When these are bombarded by constant radiation, the carefully arranged atoms get jostled out of place. The result can be eventual cracking, swelling and instability.

quot;Glasses absolutely get completely screwed up,quot; Grimes said in a telephone interview. quot;They are very, very good, cheap ways for shortish-term storage 8230; but what we are looking for is material that will last tens of thousands of years.quot;

Grimes and graduate student Lisia Minervini ran a series of computer models aimed at predicting the kind of materials that would tolerate having their atoms shifted around a bit. They came up with a kind of map, with erbium zirconate at one end and erbium titanate at the other.

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Kurt Sickafus and colleagues at Los Alamos National Laboratory in New Mexico created the two compounds and ran tests in which they bombarded them with xenon gas.

The experiments confirmed what Grimes had predicted 8211; that erbium zirconate was the best at resisting the bombardment.