SRS employees extend the lifespan of the spent fuel storage pool | Savannah River Site

A team at the Savannah River site has completed the safe removal of sediment from a tank for a basin that stores spent nuclear fuel from former production reactors and from overseas and domestic research reactor programs.

The subsea storage facility, known as the L-Disassembly Basin, holds approximately 3.4 million gallons of water with a basin depth of 17 to 50 feet. The pool water provides shielding to protect workers from radiation. The settling tank is part of a sand filter filtration system that is used to remove sediment from the basin to ensure water clarity.

“It is important that the water in the L-Basin stays clear so that operators can see what they are doing when handling fuel underwater,” said Neil McIntosh, assistant facility manager, L-Basin, Savannah River Nuclear Solutions , the management and operations contractor of SRS. “Over time, the settling tank becomes full and we have to remove the contaminated sediment and dispose of it safely.”

When the last time sediment had to be pumped out of the tank almost 20 years ago, the employees of the L-basin used a so-called sludge treatment plant, the reuse of which would require expensive modernization work.

Area L waste management workers worked with the Savannah River National Laboratory to obtain commercially available products that could safely perform sediment removal, a lower cost alternative.

“After a pump removed the water and sediment from the tank, a cloth-like membrane held the sediment back,” said McIntosh of the new, innovative system. “This material was then placed in a waste container that will be delivered to the SRS Solid Waste Management Facility, and the water was returned to the L-basin.”

The project modeled the new removal process, including replicated sediment material, to ensure the safety and adequate training of staff, as well as the functionality of the removal equipment. Hands-on individuals took part in several test runs to help develop procedures and ensure that they are implemented correctly. Team members applied various lessons learned from these activities in the final planning of sediment removal.

“The work to remove sediment from the sedimentation tank will ensure that the L-tank’s life is extended for as long as necessary,” said DOE program manager Michele O’Shaughnessy. “The collaboration, teamwork and careful planning by SRNS have helped ensure successful sediment removal in a safe and cost-effective manner.”