The DOE has tested a coal boiler at the Savannah River site in Aiken, South Carolina, that shows these results.

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Other high-risk sites facing work delays are the Oak Ridge Reservation in Tennessee, Savannah River Site in South Carolina and the Idaho National Laboratory.

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Yet reaching this point has required significant deepening of the Savannah River, from its natural depth of 17 feet (5.2 metres) to 42 feet today.

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Savannah's port is almost 20 miles (32km) inland on the Savannah River, far from the city's charming Victorian centre, in the distinctly unlovely suburb of Garden City.

ECONOMIST: Savannah's port