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@ This document was printed on recycled paper. (9197)t r SummaryThis report describes two bench-scale column tests conducted to demonstrate the removal of Tc-99 from actual alkaline high salt radioactive waste. The waste used as feed for these tests was obtained fromlhe Hanford double shell tank AW-101 , which contains double shell slurry feed (DSSF). The tank sample was diluted to approximately 5 M Na with water, and most of the Cs-137 was removed using crystalline silicotitanates. The tests were conducted with two small columns connected in series, containing 10 mL of either a sorbent, ABEC 5000 (Eichrom Industries, Inc.), or an anion exchanger Reillex?-HPQ (Reilly Industries, Inc.). Both materials are selective for pertechnetate anion (TcO4-). The process steps generally followed those expected in a full-scale process and included 1) resin conditioning, 2) loading, 3) caustic wash to remove residual feed and prevent the precipitation of Al(OH)3, and 4) elution. A small amount of Tc-99m tracer was added as ammonium pertechnetate to the feed and a portable GEA counter was used to closely monitor the process. Analyses of the Tc-99 in the waste was performed using ICP-MS .with spot checks using radiochemical analysis. Technetium x-ray absorption spectroscopy ( U S ) spectra of 6 samples were also collected to determine the prevalence of non-pertechnetate species [e.g. Tc(IV)].Some of the relevant flow test parameters are given in Table S The 1525% of the Tc-99 that was not extracted corresponds to a Tc-99 level in the effluent of 1.65 X 10-2 Cum3 to 2.75 X 10-2 Ci/m3. This is 5.5% to 9.2% of the NRC Class A limit of 0.3 Ci/m3. The concentration in the final waste form would likely be higher.The relatively high fraction of non-pertechnetate Tc-99 in the AW-101 waste suggests that this phenomenon may be common in the tank wastes. It was expected that significant fractions of non-pertechnetate Tc-99 would be restricted to tank wastes with a high organic content. The DSSF from AW-101 contains a relatively low amount of organic ( approx. 2.5 g TOC/L in tank).As indicated by the So values, the effective Tc-99 capacity of the Reillexm-HPQ is greater than that for the ABEC 5000 material. The difference between the h50 values for the Tc-99m tracer data and the actual Tc-99 data is attributed to the non-pertechnetate fraction in the waste.Both materials are efficiently eluted, but the ABEC 5000 material is eluted with deionized water which would contribute a relatively small amount of other components to a final waste form.Few operational problems were experienced with either material, although a small portion of the ReillexT"-HPQ bed on the second column was observed to float in solution and preparation of the ABEC 5000 column was tedious because of the difficulty in removing entrained air from the bed. It is suggested that a larger particle size would alleviate this problem.--

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Reprint of hirtorical document TWRSPP-sZ-020. dated 1992. Data. formatting, and Mher mmntionr reflect stardards at the origiml date of printing. Tcchnieal peer reviews and editorial reviews may r a have teen performed. Laboratory (PNL) has studied several ion exchange materials f o r the recovery of cesium from Hanford waste tanks. tasks, 1) t o obtain equilibrium data f o r cesium ion exchange, and 2) t o evaluate ion exchange column performance. The subject of this l e t t e r report ' is the measurement of batch distribution coefficients f o r several ion exchange medi,a f o r a range of operating conditions f o r two types of waste; complexant concentrate (CC) and neutralized current acid waste (NCAW) DISCLAIMERThe WHC program was divided into two main . Equilibrium data was obtained f o r the ion exchange materials IONSIV IE-96 (a zeolite produced by UOP), CS-100 (an organic resin produced by Rohm and ' Haas) and SRL-DJ (a new resorcinol-formaldehyde organic resin produced by Boulder Scientific). coefficients (Cs Kd) were obtained a t temperatures of 10°c, 25OC and 4OoC using simulated NCAW and CC wastes. Results obtained f o r the SRL-DJ exchanger were inconsistent -w i t h previous PNL results w i t h material sent from the Savannah River Laboratory (SRL). Dr. Jane Bibler (SRL) provided new material from a 50 lb l o t that was prepared by Boulder Scientific (BIB-DJj. Excellent results were obtained using the BIB-DJ resin. The following conclusions were developed a f t e r completion of the batch distribution study:Five hundred (500) cesium batch distributionThe cesium ion exchange capacity of IE-96 and CS-100 doubles as the temperature is varied from 4OoC t o 10°C. effect was not as pronounced f o r the BIB-DJ resin. The i n i t i a l volume of feed that can be processed using IE-96 inlreases w 50% w i t h a 3X feed dilution (6M Na d i l u t e d t o 2M Na ). The i n i t i a l feed volume w i t h the BIB-DJ resin decreases by ~1 0 % w i t h a 3X feed dilution, and >30% w i t h CS-100.The x values (A = cs Kd x pb) f o r cesium ion exchange a t 5~ Na' f o r NCAW and CC waste were similar; 45-57, 65-80 and 240 f o r CS-100, IE-96,4and BIB-DJ, respectively, a t an equilibrium Na/Cs mole r a t i o of 10 , a t 10°C. From these results, i t is postulated that basic ion exchange data can be applied t o a broad range of tank waste types.The temperature i i i . 4... Potassium (K' ) was found t o exert an effect on X , over a Na/K range of 11 t o 200. An increa3ing amount of K was found t o decrease the cesium X as the K competes w i t h the-cesium for ion exchange s i t e s .Rubidium was found t o have a negligible effect on X over a Na/Rb range of 1.15E4 -4.6E4 (Cs/Rb = 0.2 t o 92). While rubidium can be expected t o compete w i t h the cesium for ion exchange s i t e s , the Cs/Rb ratios tested were not small enough t o be significant.....

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