The first wall section of Saltstone Disposal Unit 8 (SDU 8) at the Department of Energy's Savannah River Site in South Carolina was installed earlier this month.

SDU 8 will stand 43 feet tall and 375 feet in diameter, and have a 33-million-gallon capacity, just like two SDUs built recently at the site. The 25 wall sections of SDU 8 are being constructed using high-strength, reinforced concrete and will be wrapped with seven layers of more than 300 miles of steel cable for added strength.

The flooring of SDU 8 is more than halfway complete. The concrete floor sits on top of a multilayer foundation: a geosynthetic clay liner and high-density plastic liner sandwiched between two concrete layers called “mud mats.” The floor is being completed in 14 sections.

The disposal units are built to safely and permanently contain decontaminated salt solution processed at Savannah River, the DOE reported on March 9.

Work crews remove the first column filled with cesium from the Tank Closure Cesium Removal unit by crane in H tank farm at the Savannah River Site. Photo: DOE

Columns filled with cesium have been removed at the Savannah River Site in a demonstration project designed to accelerate removal of radioactive salt waste from underground tanks.

“On the surface, it appeared to be like any other crane lift and equipment transport, which are routinely performed in the tank farms. However, this equipment contained cesium-rich, high-level waste, which was transported aboveground via roadway to an on-site interim safe storage pad,” said Savannah River Remediation (SRR) president and project manager Phil Breidenbach. “It was all handled safely and executed with outstanding teamwork by our highly skilled workforce.”

Operated by liquid waste contractor SRR, a system known as the Tank Closure Cesium Removal (TCCR) unit removes cesium from the salt waste in Tank 10 in the site's H Tank Farm. The TCCR is a pilot demonstration that helps accelerate tank closure at the site, according to a report by the Department of Energy on February 9.