Characterization of and Waste Acceptance Radionuclides to be Reported for the Second Macro-Batch of High-Level Waste Slu
- PDF / 1,171,607 Bytes
- 6 Pages / 414 x 635.4 pts Page_size
- 72 Downloads / 167 Views
607 Mat. Res. Soc. Symp. Proc. Vol. 608 0 2000 Materials Research Society
EXPERIMENTAL
Combination of the Sludge Slurry Samples Six samples of Macro-Batch 2 sludge slurry from SRS Tank 51 were received at SRTC in 80 mL stainless steel bottles. These sludge slurry samples were placed into the SRTC Shielded Cells and then combined into a one-liter container. To ensure all of the sludge slurry solids had been removed from each stainless steel bottle, each bottle was carefully rinsed. The final volume of the combined sludge slurry was -454 mL with about 19 wt. % solids. Analytical Methods Dissolution of the Macro-Batch 2 sludge slurry sample was performed remotely in the Shielded Cells of SRTC. A portion of the sludge slurry sample was dissolved in quadruplicate by two separate dissolution methods. Details of these dissolution methods have been published [2]. Prior to dissolution, the sludge slurry was dried at 115*C in a drying oven. A standard glass with a composition similar to the DWPF glass, Analytical Reference Glass-1 (ARG-1) [3], was also dissolved and analyzed concurrently with the sludge slurry samples. This was done to confirm that the dissolutions were complete and the analytical procedures were performed correctly. The dissolved samples were diluted so that only a small potion of the radioactivity was removed from the Shielded Cells. The resulting solutions were then analyzed using ICP-ES, AA, ICP-MS and counting techniques. Identification of Reportable Radionuclides for Macro Batch 2 In order to determine the reportable radionuclides for Macro-Batch 2 all radioactive U-235 fission products and all radioactive activation products that could be in the SRS HLW were considered. It was evident that some of the radioisotopes in the sludge slurry could not be measured because of their low concentration in the sludge slurry. For these isotopes, an estimate of the concentration was made by calculating their concentration based on their U-235 fission yields. An estimate of the concentrations for Se-79, Rb-87, Pd-107, In-1 15, Sn-121m and Sn-126 was done in this way. This was accomplished by dividing the fission yield (a known yield value from the fission of U-235) for each isotope by the average Fission Yield Scaling Factor (FYSF). The average FYSF is determined by calculating a FYSF (known fission yield / elemental wt. %) for appropriate low and high mass fission products and averaging the results. Details concerning the calculation of the FYSF and the fission products that are appropriate have been published [4]. Figures 1 and 2 present the measured and calculated concentrations for the low mass and the high mass U-235 fission products that could be detected for Macro-Batch 2. Explanations for those concentrations that deviate from the calculated concentrations have been published [4]. For example, results at masses 88,107,110, and 140 can be assigned to natural Sr, Ag, Cd, and Ce isotopes in the waste. After determining and estimating the concentrations for all of the radioactive U-235 fission products and al
Data Loading...
