Gooey Gel May Help Clean Nuclear Spills

["Sandy Perle" <sandyfl@earthlink.net>]

Thursday October 7 12:33 AM ET 

Gooey Gel May Help Clean Nuclear Spills  

LONDON (Reuters) - A gooey yellow gel containing concrete-eating 
bacteria could help to clean up nuclear spills, New Scientist 
magazine said Wednesday.  

Researchers at British Nuclear Fuels (BNFL) and the Idaho 
National Engineering and Environmental Laboratory (INEL) in Idaho 
Falls have already tested the gel in the laboratory. They will soon 
be putting it to work at Britain's Sellafield nuclear processing plant.  

``In the next two months it will be applied to contaminated concrete 
inside a walkway near the chimney at the Windscale Pile 1 
reactor, where some of the contamination dates from a fire in 
1957,'' the weekly science magazine said.  

The gel contains the bacterium Thiobacillus thiooxidans, which is 
one of the causes of corrosion in concrete buildings and bridges.  

``It feeds on sulfur-containing compounds in the concrete and 
converts them into dilute sulfuric acid, which eats away at any 
concrete it meets,'' the magazine said.  

Scientists mixed the bacteria with sulfur and added a thickening 
agent to give it the consistency of custard, allowing it to be spread 
or sprayed on concrete.  

``Humidifiers are used to keep the humidity level around the gel at 
about 95 percent, which allows T. thiooxidans to thrive and 
continue churning out acid,'' the magazine added.  

When the gel has done its work engineers allow it to dry, which 
kills the bacteria, and then the waste is collected and disposed.  

``These critters deliver the acid to precisely where you want it,'' 
said BNFL project manager Tim Milner.  

The drawback is the slowness of the process. The bacteria eats 
through concrete at the rate of about half an inch a year. But Milner 
said this was not a problem because most contamination occurs in 
the top few millimeters of a surface.

------------------------
Sandy Perle
E-Mail: sandyfl@earthlink.net
Personal Website: http://www.geocities.com/capecanaveral/1205

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