Distributions of 15 elements on 58 absorbers from simulated Hanford Double-Shell Slurry Feed (DSSF)

Marsh, S.P.; Svitra, Z.V.; Bowen, S.M.

doi:10.2172/10113481

Cited by 22 publications

(13 citation statements)

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“…Technetium removal by ion exchange has also been investigated by several researchers at Los Alamos National Laboratory (LANL). Various ion exchange materials removed technetium as pertechnetate from various simulated solutions (Marsh et al 1994a;Marsh et al 1994b;Marsh et al 1994c;Marsh et al 1995). Much of the recent research concerning technetium removal has focused on the ReillexTW€PQ resin (Schroeder et al 1993;Schroeder et al 1994;Schroeder et al 1995% Schroeder et al 1995b) and ABEC 5000 sorbent (Rogers et al, 1996).…”

Section: Needmentioning

confidence: 99%

Technetium in alkaline, high-salt, radioactive tank waste supernate: Preliminary characterization and removal

Blanchard¹,

Brown²,

Conradson³

1997

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SummaryThis report describes the initial work conducted at Pacific Northwest National Laboratory to study technetium (Tc) removal fiom W o r d tank waste supernates and Tc oxidation state in the supemates. Filtered supernate samples fiom four tanks were studied: a composite double shell slurry feed (DSSF) consisting of 70% fiom Tank AW-101, 20% from AP-106, and 10% fiom AP-102; and three complexant concentrate (CC) wastes (Tanks AN-107, SY-101, ANS SY-103) that are distinguished by having a high concentration of organic complexants. The work included batch contacts of these waste samples with ReillexTW€PQ (anion exchanger fiom Reilly Industries) and ABEC 5000 (a sorbent from Eichrom Industries), materials designed to effectively remove Tc as pertechnetate fiom tank wastes. A short study of Tc analysis methods was completed. A preliminary identification of the oxidation state of non-pertechnetate species in the supernates was made by analyzing the technetium x-ray absorption spectra of four CC waste samples. Molybdenum (Mo) and rhenium (Re) spiked test solutions and simulants were tested with electrospmy ionizationmass spectrometry to evaluate the feasibility of the technique for identifying Tc species in waste samples.The highlights fiom the work are as follows:* Both ReillexTH-HPQ and ABEC 5000 are effective for Tc removal from the composite DSSF waste (70% AW-IOl), exhibiting 93% and 91% removal, respectively, on the first contact. Neither Rei1lex"cHpQ nor ABEC 5000 are effective for Tc removal from the three CC wastes studied. Technetium removal from the CC wastes was in all cases less than 50%. Removal of Tc from these wastes will require either an alternative process such as electrochemical deposition or addition of a feed adjustment step to oxidize the Tc species to pertechnetate.The Tc in CC waste is very resistant to oxidation to pertechnetate in acidified samples generally required for Tc analysis. A vigorous oxidation with C e O was found effective for this purpose, but is time consuming. X-ray absorption near edge spectroscopy indicates that the dominant species in CC waste is not pertechnetate. It also shows that the non-pertechnetate specie(s) in the CC wastes probably has an oxidation state of +IV.The batch contacts, oxidation study, and XANES data all indicate that for the tested wastes containing relatively large (> 10 g total organic carbon per liter), amounts of organic complexants, more than half of the total Tc is not pertechnetate.Inductively coupled plasma-mass spectrometry identified Re species, including polyoxyanions, in simulants and test solutions and was usefid for following the Re species through various changes in solution chemistry. Penhenate, a good surrogate for TcOi, was easily detectable in a CC waste simulant at 200 m a , somewhat higher than the concentration of Tc in CC wastes.

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Section: Needmentioning

confidence: 99%

Technetium in alkaline, high-salt, radioactive tank waste supernate: Preliminary characterization and removal

Blanchard¹,

Brown²,

Conradson³

1997

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“…Technetium removal by ion exchange has also been investigated by several researchers at Los Alamos National Laboratory (LANL). Various ion exchange materials have shown the ability to remove technetium as pertechnetate from various simulated solutions (Marsh et al, 1994a;Marsh et al, 1994b;Marsh et al, 1994c;Marsh et al, 1995). Much of the recent research concerning technetium removal has focused on the ReillexTM-HPQ resin (Schroeder et al, 1993;Schroeder et al, 1994;Schroeder et al, 1995a;Schroeder et al, 1995b) and ABEC 5000 sorbent .…”

Section: Needmentioning

confidence: 99%

Technetium removal column flow testing with alkaline, high salt, radioactive tank waste

Blanchard¹,

Kurath²,

Golcar

et al. 1996

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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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“…Separation of the cesium from the liquid-based waste was defined by the most current separation factors (i.e., K,) for the organic (Marsh et al, November 1994 andMarsh et al, December 1994) and inorganic (Miller & Brown, 1997) resins. 4.…”

Section: Discussionmentioning

confidence: 99%

A Cost Comparison of Organic versus Inorganic Ion Exchange Resin for Remediation of High‐Level Waste

DeMuth¹

1999

Remediation Journal

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Distributions of 15 elements on 58 absorbers from simulated Hanford Double-Shell Slurry Feed (DSSF)

Cited by 22 publications

References 4 publications

Technetium in alkaline, high-salt, radioactive tank waste supernate: Preliminary characterization and removal

Technetium in alkaline, high-salt, radioactive tank waste supernate: Preliminary characterization and removal

Technetium removal column flow testing with alkaline, high salt, radioactive tank waste

A Cost Comparison of Organic versus Inorganic Ion Exchange Resin for Remediation of High‐Level Waste

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