High levels of mercury and a faulty valve were recently discovered in Savannah River Site’s aging, highly radioactive nuclear waste storage tanks.
Savannah River Site spokesman Jim Giusti stated Thursday in a news release the incidents with the liquid-waste system were reported to the U.S. Department of Energy by site contractor Savannah River Remediation. No workers were injured or exposed to mercury, and corrections continue.
In February, the tank system was evaluated after high mercury levels were detected in liquid waste salt streams, according to the release. The mercury did not exceed waste disposal permit levels but were “higher than internal safety controls allow,” the release stated.
The site has 51 underground storage tanks, six of which are no longer in use. Some were built in the 1950s and age and structural integrity have been concerns for environmental regulators.
SRR monitors mercury levels known to exist in liquid waste. Waste samples taken during the February evaluation and analyzed by Savannah River National Laboratory showed trace levels of monomethylmercury, an organic mercury compound, Giusti said. Monomethylmercury can be harmful if it contacts skin. Workers are required to wear special gloves for added protection and voluntary medical testing has been offered, he said.
The other incident occurred March 11 and March 25 when liquid waste was transferred to the wrong tank because of a degraded waste transfer valve and valve actuator, according to the news release. When a valve actuator failed to fully close, nearly 6,600 gallons of waste was incorrectly transferred from a tank with a capacity of 1.3 million gallons. The valve was closed but failed again, the release said.
The site has made efforts to replace the faulty valve and seven others. Some waste transfers have resumed.