selected by representatives at the Savannah River Site for processing the high-level radioactive waste salt solutions stored there in tanks. The work of that committee was completed and its findings were reported in Alternatives for High-Level Waste Salt Processing at the Savannah River Site (National Research Council, 2000).
After receiving that report, DOE asked the NRC to provide additional advice on the waste processing efforts at the SRS, and a new committee was impaneled to examine the DOE's selection of a process for separating radionuclides from soluble high-level radioactive waste at that site. This newly constituted committee consists of six members of the previous committee, plus three new members whose areas of expertise were needed to address the new charge. The committee was charged with a three-part task:
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evaluate the adequacy of the criteria that will be used by DOE to select from among the candidate processes under consideration;
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evaluate the progress and results of the research and development work that is undertaken on these candidate processes; and
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assess whether the technical uncertainties have been sufficiently resolved to proceed with downsizing the list of candidate processes.
The committee may, at its discretion, also provide comments on the implementation of the selected process.
The purpose of this brief interim report is to address the first of the three tasks.
BACKGROUND
At present three alternative processes remain under consideration for removal of cesium, strontium, and actinides from tank supernate solutions at SRS; namely, small tank precipitation by tetraphenylborate (TPB), ion exchange on crystalline silicotitanate, and caustic side solvent extraction. A brief description of the site's high-level waste program, described in Alternatives for High-Level Waste Salt Processing at the Savannah River Site (National Research Council, 2000), is included in this report asAppendix C. A key recommendation in that report was the following:
The committee finds that there are potential barriers to implementation of all of the alternative processing options. The committee recommends that Savannah River proceed with a carefully planned and managed research and development (R&D) program for three of the four alternative processing options (small tank precipitation using TPB,crystalline silicotitanate ion exchange, and caustic side solvent extraction, each including monosodium titanate processing for removing strontium and actinides) until enough information is available to make a more defensible and transparent downselection decision. The budget for this R&D should be small relative to the total cost of the processing program, but this investment will be invaluable to overcoming many of the present uncertainties discussed in this report.