At least19 wells will be replaced. The corrosion seems to be caused by normal soil conditions and not from leaking contaminants.
By Bill Bartleman firstname.lastname@example.org
The replacement of at least 19 monitoring wells damaged by severe corrosion will start this spring at the Paducah Gaseous Diffusion Plant.
The wells are located around landfills outside the plant's fenced area on Ogden Landing Road. Regular samples are taken from the wells to monitor the spread of trichlorethylene, technetium 99 and other contaminants. Trichloroethylene is a solvent once used to clean equipment in the nuclear fuel plant, while technetium 99 is a radioactive isotope.
There are 135 wells monitored for compliance of state environmental regulations, according to Greg Cook, spokesman for Bechtel Jacobs Co., which manages cleanup at the plant. Cook said other wells also show signs of corrosion.
"We don't know how many others may need to be replaced," he said. "We are still looking at that."
A 150-page report prepared for the Kentucky Natural Resources Cabinet says the corrosion in the 1/16th-inch stainless steel casing is caused by enzymes created by bacteria in the groundwater and around the wells. The enzymes are known as microbial agents.
"The state is not satisfied that the samples (from the corroded wells) are completely reliable," Cook said. "We aren't happy with the situation either, so they'll have to be replaced."
The 19 new wells could cost the U.S. Department of Energy as much as $1.5 million, Cook said. Money earmarked for other cleanup and monitoring would be diverted to the well replacements.
The report, under review by state environmental regulators, said there is no evidence that the corrosion was caused by contaminants leaking from the plant.
Cook said it is a problem that could occur in any well and appears to be related to western Kentucky soil conditions. The wells, installed in the early 1990s, are 50 to 100 feet deep.
Cook said alternatives to stainless steel are being studied, and that the likely alternative will be plastic, which he said is resistant to corrosion.