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:
1. evaluate the adequacy of the criteria that will be used by the department to select from among the candidate processes under consideration;
2. evaluate the progress and results of the research and development work that is being undertaken on these candidate processes; and
3. 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. This report 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."