After spending more than a year offline, the only chemical separation facility operating in the United States is restarting spent fuel dissolution work.
At the L Area Complex in the Savannah River Site (SRS), high and low enriched spent nuclear fuel is stored in underwater storage facilities called disassembly basins. In 1998, Savannah River opted to consolidate all of its spent fuel storage in the L Basin facility.
The L Basin facility has concrete walls, is 17 to 50 feet deep, and holds approximately 3.5 million gallons of water which keeps the fuel rods cool and protects workers from radiation.
Spent nuclear fuel has been filling up the L Basin storage facility, which is nearing capacity. This has forced SRS staff to restart spent nuclear fuel processing operations.
As of 2012, the L Basin facility was storing 3,174 spent nuclear fuel assemblies and had enough room installed for 3,650 assemblies. The facility also held 120 high flux isotope reactor cores which were all it was approved to hold.[i]
Workers at the H Canyon processing facility at the SRS will conduct operations processing up to 1,000 spent nuclear fuel bundles from the Material Test Reactor and 200 offloaded cores of spent fuel from high flux isotope reactors which are currently stored at the site. Fuel from Material Test Reactors can have up to 93% U-235.[ii]
The goal is to employ a chemical process to separate the high-enriched uranium from the spent fuel rods and down blend it with natural uranium to make new fuel rods for commercial nuclear reactors in the United States.
The fission products and plutonium separated from the fuel rods will be transferred to the high level waste system where they eventually will be vitrified into glass at the Defense Waste Processing Facility at Savannah River.
During surveillance of the L Basin in 2011, workers discovered mysterious “cobwebs” covering the tops of spent fuel bundles in the spent fuel pool. Samples were taken and analyzed. The analysis showed that the cobwebs were made up of bacteria and microbes.
Workers tried vacuuming the top of the fuel racks, which had never been done before. Some areas were coated with cobwebs so thick that it took three years for all of them to be removed.[iii]
The Department of Energy still needs to form an official decision on the future of the spent fuel in the L Basin facility, whether to pursue dry storage or continue reprocessing. Analysts from the Savannah River National Laboratory published a study in 2011 which concluded that the spent fuel could be stored at the SRS site for an additional 50 years.