SRS giant storage unit okayed for start

April 22, 2024, 12:10PMRadwaste Solutions
SDU 9 is the latest megavolume disposal unit completed at SRS. (Photo: DOE)

The Department of Energy’s Office of Environmental Management has authorized the newest megavolume disposal unit to begin operating at the Savannah River Site in South Carolina.

The authorization marks the last step before saltstone disposal unit (SDU) 9 can begin receiving decontaminated material for disposal, according to DOE-EM. The unit was completed more than $60 million under budget and seven months ahead of schedule, the office noted.

The SDUs: Recent SRS accomplishments have included construction completion of SRS’s megavolume SDU 8 last year and SDU 7 in 2021.

SDU 9 is the fourth large unit built at SRS and can hold up to 33 million gallons of saltstone. These SDUs are designed to support the increased material production from the site’s Salt Waste Processing Facility (SWPF). The new SDUs will result in more than $500 million in cost savings over the life of the SRS Liquid Waste Program, because they require less infrastructure and materials than the previously planned 80 smaller SDUs, according to DOE-EM.

Savannah River Mission Completion (SRMC), the office’s liquid waste contractor, is also in various stages of constructing SDUs 10, 11, and 12—the final units needed at SRS. SDU 10 is under construction, while sites have been prepared for SDUs 11 and 12 with mud mat construction beginning for SDU 11 this year.

The SDUs are the end of the salt waste processing path, according to DOE-EM. SWPF produces decontaminated material that is sent to the Saltstone Production Facility, where it is mixed with dry materials to make a cement-like grout. The grout is then pumped into the SDUs, where it solidifies into a monolithic, nonhazardous form.

Materials: The radioactive liquid waste generated at SRS are byproducts from processing nuclear materials for national defense, research, medical programs, and NASA missions. The waste—totaling 33 million gallons—is stored at SRS in two groupings of underground waste tanks in tank farms.

The contractors: In addition to SRMC, which manages the construction and operation of the SDUs, subcontractors Quality Plus Services, US Fusion & Specialty Construction, and DN Tanks completed the site preparation, interior and exterior liner systems, and unit construction.

Quote: Jim Folk, DOE-Savannah River assistant manager for waste disposition, said, “These units play a critical role in EM’s commitment to undertaking one of the largest environmental cleanup efforts in the country. The mega-size saltstone disposal units are vital in our ability to safely dispose of legacy liquid waste and underscore DOE’s commitment to complete the SRS Liquid Waste Program.”

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