Microorganisms that corrode metal have been discovered in the ponds where spent nuclear fuel rods are stored. Safety experts fear that the bacteria could cause leaks in the metal cladding around the fuel rods.
The Westinghouse Savannah River Company, which manages the Savannah River nuclear repository in Aiken, South Carolina, presented the findings last week in Atlanta. "If you get large amounts of microbial growth, it could become a problem," says Carl Fliermans, who heads a team investigating the phenomenon at the Savannah River Technology Center.
The water which shields stored fuel rods is supposed to be sterile and free of the nutrients that bacteria need to grow. "We've had these systems going since the mid-1950s and we've not seen a problem with corrosion," says Fliermans.
The finding that metal-munching bacteria can thrive in the barren environment of the storage ponds is ill-timed: a worldwide downturn in nuclear reprocessing means that in some countries the rods are being stored for years, rather than the few months that was intended.
Fliermans and his colleagues discovered the problem when they examined samples of cladding materials that had been dunked in seven of the eight basins at Savannah River for up to a year. The samples were tiny rods, each 1 centimetre long, imbedded in Teflon and lowered to four different depths beside the fuel rods.
Andy Coghlan
New Scientist issue date 30th May 1998, page 6
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The New Scientist