Savannah River Site liquid waste workers sealed the deal by capping off a cracked vault that started leaking radionuclides back in 2013.
Savannah River Remediation, the liquid waste contractor in charge of the project, reported this week that workers finished adding a clean grout cap and an elastomeric roof coating to all 12 cells in Saltstone Disposal Facility.
The facility houses the mixture of low-radioactive treated salt solution and cement and other products that help dilute the waste.
"Completion of this work mitigates the environmental risk of any potential radioactive contamination migration," a press release stated.
Construction of the Vault 4 disposal unit was completed in 1988, and it started receiving a low-level waste grout mixture, called saltstone, in 1990. Vault leakage was first noticed in February 2013, and Energy Department officials reported that the leakage stemmed from cracks in the roof of the vault.
Contaminated liquid had leaked through Vault 4 cracks and construction joints, and small damp spots had been observed on the outside of the vault walls caused by seepage of liquid through cracks in the concrete walls. The condition was further aggravated by rainwater in-leakage.
On July 31, 2013, SRS submitted a letter to the S.C. Department of Health and Environmental Control outlining the issue and the site's repair efforts. The contractor provided a temporary fix while working to close Vault 4 by covering the 12 cells with a more permanent, elastomeric roof coating.
A clean grout cap was the first step toward installing the elastomeric coating, allowing the workers to safely access the roof while keeping radiation dose rates as low as possible.
"The recently installed elastomeric roof covering will prevent in-leakage of rainwater into the Vault 4 cells, which in turn will mitigate migration of radioactive contamination," the contractor reported in a press release.
Vault 4 continues to be inspected on a routine basis, and the vault is inspected monthly by the Department of Health and Environmental Control.
Derrek Asberry is the SRS beat reporter for the Aiken Standard and has been with the paper since June 2013. He is originally from Vidalia, Ga., and a graduate of Georgia Southern University. Follow him on Twitter @DerrekAsberry.