Savannah River Site Disposal Facility for Waste Incidental to Reprocessing
The Savannah River Site (SRS), owned by the U.S. Department of Energy (DOE), occupies an area of approximately 780 km2 (300 mi2) in western South Carolina. Since its establishment in 1951, SRS has produced nuclear material for national defense, research, medical applications, and space programs. As a result of these activities, SRS now has significant quantities of radioactive waste stored onsite in large underground waste storage tanks. Over the years, however, the waste resulting from reprocessing spent nuclear fuel for defense purposes has been commingled with other types of waste resulting from manufacturing targets for nuclear weapons and fabricating materials for space missions.
DOE now intends to remove, stabilize, and dispose of the waste, and close all 51 operational waste storage tanks at SRS. The sludge (insoluble metal hydroxide solids) is currently being stabilized in the Defense Waste Processing Facility (DWPF) through a vitrification process, which immobilizes the waste in a borosilicate glass matrix for eventual disposal in a Federal repository. In order to continue to have adequate tank farm space to support DWPF operations and startup of the Salt Waste Processing Facility (SWPF), however, DOE has indicated that it needs to remove a portion of the salt waste in the near term. For additional detail, see the following topics on this page:
SRS Waste Characterization
SRS currently has a total of 51 underground waste storage tanks, all of which were placed into operation between 1954 and 1986. Of those 51 tanks, only 27 meet the current requirements, established by the U.S. Environmental Protection Agency (EPA), for full secondary containment and leak detection. Another 4 tanks, which did not have secondary containment, have already been closed and grouted. The remaining 20 tanks do not have full secondary containment and do not meet EPA requirements. (Of those 20 tanks without secondary containment, 12 have a history of leakage, but sufficient waste has been removed so that those tanks currently have no active leak sites.) Of the 47 tanks that are not yet closed, 29 are in the H-Tank Farm and 18 are in the F-Tank Farm.
The SRS waste storage tanks hold waste that is a mixture of insoluble metal hydroxides (referred to as sludge), and soluble salt supernatant (the liquid above a precipitate or sediment). The volume of supernatant has been reduced by evaporation, which also concentrates the soluble salts to the limits of their solubility. The resultant solution crystallizes as salts, and the resulting solid is referred to as saltcake.
SRS Saltstone Disposal Facility (SDF)
In March 2005, DOE submitted a draft waste determination, describing its plan to dispose of the salt waste at SRS. In particular, DOE proposed to remove salt waste from the 49 operational waste tanks at SRS, treat the waste with various processes to remove some of the radionuclides in the waste, and solidify the treated salt waste by mixing it with dry grout ingredients to form a cementitious wasteform called saltstone.
Based on a review of DOE's draft waste determination and supporting documents, the NRC staff concluded that there is reasonable assurance that the salt waste will meet the applicable criteria for designation as waste incidental to reprocessing (WIR), provided that several key assumptions are verified during monitoring. That conclusion and the NRC staff's review are documented in the Technical Evaluation Report for SRS Saltstone Disposal, and the NRC staff issued its related Monitoring Plan in May 2007.
In November 2009, DOE submitted a revised SDF performance assessment for NRC review. Based on that review, NRC staff concluded that it has reasonable assurance that waste disposal at the SDF meets the 10 CFR Part 61 performance objectives for protection of individuals against intrusion (§61.42), protection of individuals during operations (§61.43), and site stability (§61.44). However, based on its evaluation of DOE's results and independent sensitivity analyses conducted with DOE's models, the NRC staff no longer has reasonable assurance that DOE's disposal activities at the SDF meet the performance objective for protection of the general population from releases of radioactivity (§61.41).
Under Section 3116(b) of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), if the NRC considers any disposal actions taken by DOE to be not in compliance with the Part 61 performance objectives, then NRC must, as soon as practicable after discovery of the noncompliant conditions, inform DOE, Covered State, and specific Congressional committees. Based on that NDAA responsibility, in NUREG-1854, NRC developed a process to inform DOE, Covered State, and/or Congress if specific things occurred during NRC's monitoring of DOE disposal actions, including a Letter of Concern to DOE and the Covered State.
Details of the NRC staff review of the 2009 SDF performance assessment and the NRC conclusions are documented in the April 2012 TER with the associated NRC Letter of Concern. In 2013, NRC staff issued its revised SDF Monitoring Plan.
SRS F-Tank Farm (FTF)
In fiscal year 2010, DOE submitted a draft waste determination to NRC that concluded that stabilized waste residuals in FTF tanks and auxiliary components, as well as the tanks and auxiliary components themselves, could meet NDAA criteria for WIR at the time of closure. Based on the NRC staff review of DOE's draft waste determination, including performance assessment and other documents, the NRC staff made a number of recommendations that NRC believes, if implemented by DOE, will enhance the DOE demonstration that FTF disposal actions would meet the performance objectives in 10 CFR Part 61, Subpart C during the FTF closure process. The NRC staff's review is documented in the Technical Evaluation Report). In January 2013, the NRC staff issued its related FTF Monitoring Plan).