Alternatives For High Level Waste Salt Processing At The Savannah River Site

The Second World War introduced the world to nuclear weapons and their consequences. Behind the scene of these nuclear weapons and an aspect of their consequences is radioactive waste. Radioactive waste has varying degrees of harmfulness and poses a problem when it comes to storage and disposal. Radioactive waste is usually kept below ground in varying containers, which depend on how radioactive the waste it. High-level radioactive waste (HLW) can be stored in underground carbon-steel tanks. However, radioactive waste must also be further immobilized to ensure our safety. There are several sites in the United States where high-level radioactive waste (HLW) are stored; including the Savannah River Site (SRS), established in 1950 to produce plutonium and tritium isotopes for defense purposes. In order to further immobilize the radioactive waste at this site an in-tank precipitation (ITP) process is utilized. Through this method, the sludge portion of the tank wastes is being removed and immobilized in borosilicate glass for eventual disposal in a geological repository. As a result, a highly alkaline salt, present in both liquid and solid forms, is produced. The salt contains cesium, strontium, actinides such as plutonium and neptunium, and other radionuclides. But is this the best method? The National Research Council (NRC) has empanelled a committee, at the request of the U.S. Department of Energy (DOE), to provide an independent technical review of alternatives to the discontinued in-tank precipitation (ITP) process for treating the HLW stored in tanks at the SRS. Alternatives for High-Level Waste Salt Processing at the Savannah RIver Site summarizes the finding of the committee which sought to answer 4 questions including: "Was an appropriately comprehensive set of cesium partitioning alternatives identified and are there other alternatives that should be explored?" and "Are there significant barriers to the implementation of any of the preferred alternatives, taking into account their state of development and their ability to be integrated into the existing SRS HLW system?"

The U.S. Department of Energy (DOE) is nearing a decision on how to process 30 million gallons of high-level radioactive waste salt solutions at the Savannah River Site in South Carolina to remove strontium, actinides, and cesium for immobilization in glass and eventual shipment to a geologic repository. The department is sponsoring research and development (R&D) work on four alternative processes and plans to use the results to make a downselection decision in a June 2001 time frame. The DOE requested that the National Research Council help inform this decision by addressing the following charge: evaluate the adequacy of the criteria that will be used by the department to select from among the candidate processes under consideration; evaluate the progress and results of the research and development work that is being undertaken on these candidate processes; and assess whether the technical uncertainties have been sufficiently resolved to proceed with downsizing the list of candidate processes. Responses to the last two points are provided in this report. Research and Development on a Salt Processing Alternative for High-Level Waste at the Savannah River Site focuses exclusively on the technical issues related to the candidate processes for radionuclide removal from high-level waste salt solutions at SRS. The committee's interim report served as a response to the first point of this charge, and may be read in Appendix B. In that report, the committee found that DOE's proposed criteria are an acceptable basis for selecting among the candidate processes under consideration, but that the criteria should not be implemented in a way that relies on a single numerical "total score."

DOE Tank Waste: How clean is clean enough? The U.S. Congress asked the National Academies to evaluate the Department of Energy's (DOE's) plans for cleaning up defense-related radioactive wastes stored in underground tanks at three sites: the Hanford Site in Washington State, the Savannah River Site in South Carolina, and the Idaho National Laboratory. DOE plans to remove the waste from the tanks, separate out high-level radioactive waste to be shipped to an off-site geological repository, and dispose of the remaining lower-activity waste onsite. The report concludes that DOE's overall plan is workable, but some important challenges must be overcomeâ€"including the removal of residual waste from some tanks, especially at Hanford and Savannah River. The report recommends that DOE pursue a more risk-informed, consistent, participatory, and transparent for making decisions about how much waste to retrieve from tanks and how much to dispose of onsite. The report offers several other detailed recommendations to improve the technical soundness of DOE's tank cleanup plans.