Officials discovered leaks into a vault that holds low-level radioactive nuclear waste caused some environmental contamination at the Savannah River Site (SRS), according to new documents released by a nuclear watchdog group Wednesday.
Friends of the Earth released a July 31 letter from the U.S. Energy Department to South Carolina health regulators addressing their concerns about the leak discovered on February 13. The anti-nuclear Friends of the Earth monitors cleanup operations at the former nuclear weapons site in Aiken County. The group said it obtained the letter through a Freedom of Information Act request.
The letter from Terry Spears, SRS’s assistant manager of its Waste Disposition Project, says that cracks appeared in the concrete roof of Vault 4. Vault 4 holds “saltstone,” which is a low-activity byproduct of the cleanup process that is still radioactive.
The cracks (which DOE officials blame on temperature differences) allowed rainwater to get inside the vault’s cells. The runoff water became contaminated with radionuclides as it flowed into a special retention pond, as designed. However, heavy rains in June and July led to discharges from the pond into nearby McQueen’s Branch.
A spokesman for the site’s contractor Savannah River Remediation said the amount of radionuclides discharged was within safety limits. “SRR has met with the South Carolina Department of Health and Environmental Control to discuss the discharges,” Rick Kelley said in a statement. “There were low levels of contaminants in the discharge that were within federal release limits.”
SRR says no contamination has been detected at the site’s groundwater wells.
Kelley said contractors repaired the cracks immediately upon discovering them. No additional saltstone will be placed at the 25-year-old Vault 4, in favor of storage facilities with newer designs. Kelley added a more permanent elastic coating will be installed on Vault 4 next year, which will eliminate rainwater infiltration.
Friends of the Earth’s Southeastern nuclear campaign coordinator Tom Clements said he believes federal officials responded appropriately to the leak. However, he said the concrete cracks are worrisome for a structure that is designed to be a permanent storage vault.
“It does show that rainwater running off from this vault area can definitely get into the environment,” he told South Carolina Radio Network.
Clements emphasized that, while the February leak does not appear to be a health threat, it raises issues about the future. “It’s not good that this leaked, but they caught it. It’s the long-term leakage from all these materials that’s a concern.”
SRS officials say the Saltstone facilities are specifically designed so that any waste which leaches out of the vaults will still be within safe drinking water standards.