The Department of Energy has approved its latest jumbo-sized saltstone disposal unit for operation at the Savannah River Site in South Carolina, the agency said Tuesday.
Saltstone Disposal Unit 9 (SDU 9) is the fourth such mega unit built at Savannah River to hold up to 33 million gallons of saltstone, DOE said in a press release. SDU 8 was approved by DOE last July. The saltstone is separated from liquid radioactive waste that is treated elsewhere on site.
BWX Technologies-led Savannah River Mission Completion is building SDU 10 while sites have been prepared for SDUs 11 and 12. Mud mat construction for SDU 11 was to begin this year, according to the press release. The SDUs receive a cement-like grout from Saltstone Production Facility.
DOE’s fiscal 2025 budget request zeros out construction funding for SDUs 8 and 9 at Savannah River, which was enacted for about $32 million in fiscal 2024. The request also seeks $83 million for disposal units 10, 11 and 12, which were budgeted at $56 million in fiscal 2024.
SDU 8 and 9 were basically built in tandem or “bundled” at a combined cost of $218 million, which would amount to $109 million per unit, which is below the $280 million total cost DOE anticipated, a DOE spokesperson said by email.
The Savannah River Site is working through about 35 million gallons of high-level radioactive liquid waste stored in underground tanks, according to the state Department of Health and Environmental Control. The waste is a byproduct from decades of processing nuclear materials for nuclear weapons.
