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High sensitivity technetium analysis using negative thermal ionization mass spectrometry

Description: Determination of the reaction products of solar neutrinos with /sup 98/Mo and /sup 97/Mo to produce /approximately/10/sup 8/ atoms of /sup 98/Tc and /sup 97/Tc in 10/sup 4/ tons of ore for the last several million years have prompted the development of highly sensitive isotopic analytical technique for technetium. Secular equilibrium /sup 99/Tc, present in the ore at 10/sup 8/ to 10/sup 9/ atom levels will be used for an internal tracer to fix absolute atom amounts. Previous work has suggested that negative thermal ionization can produce high ionization efficiency for certain selected elements, including technetium. Negative thermal ionization has several advantages over the positive ion approach. Technetium forms the pertechnetate ion while the most common and abundant isobaric impurity, molybdenum, forms MoO/sub 3//sup /minus//. In addition, technetium forms negative ions very efficiently; efficiencies of >2% have been measured. Positive ion techniques are much less efficient. Organic impurities also are much less troublesome in the negative ionization mode. 6 refs.
Date: January 1, 1988
Creator: Rokop, D.J.; Schroeder, N.C. & Wolfsberg, K.
Partner: UNT Libraries Government Documents Department

Recovery of Technetium and Iodine from Spent ATW TRISO Type Fuels.

Description: The Accelerator Transmutation of Waste (ATW) program is being developed to determine the feasibility of separating and transmutating the transactinides (Pu-Cm) and long-lived fission product (99Tc and 129I) from spent LWR fuel. Several types of ATW fuels have been suggested to transmutate the Pu-Cm fraction including TRISO type fuels. An ATW TRISO fuel would consist of a Pu-Cm oxide kernel surrounded by several layers of pyrolytic carbon, a layer of SiC, and an outer layer of pyrolytic carbon. Processing of the spent ATW fuel would involve the crush, burn, and leach approach used on normal TRISO fuels. This report describes experiments that determine the potential behavior of the two long-lived fission products, 99Tc and 129I, in this processing. Iodine can be removed and trapped during the burning of the carbon from the fuel. Some technetium may volatilize in the latter stages of the burn but the bulk of it will have to be recovered after dissolution of the oxide residue.
Date: January 1, 2001
Creator: Schroeder, N. C. (Norman C.) & Attrep, Moses
Partner: UNT Libraries Government Documents Department

Technetium and Iodine Separations in the UREX Process.

Description: The Accelerator Transmutation of Waste (ATW) program is being developed to determine the feasibility of separatin and transmutating the transactinides (Pu-Cm) and long-lived fission product (99Tc and 'I) from spent light water reactor (LWR) fuel. This approach would help with the disposal of spent commercial fuel. In addition, since the residual waste after ATW treatment will have much lower levels of long-lived species, this process may improve the performance and acceptability of long-term geologic disposal of nuclear waste. A roadmap for the Accelerator Transmutation of Waste (ATW) was submitted to Congress in 1999.' This document gave an overall view of the ATW concept and program. A subsequent document prepared by the Technical Working Group for ATW Separations Technologies and Waste Forms issued a second roadmap that dealt more specifically with the radionuclide separations and waste disposal needs for the ATW program.' This latter document discusses the UREX (Uranium Extraction) process. The latest iteration of the UREX flowsheet is shown in Figure le3T his flowsheet anticipates the co-extraction of technetium with uranium from dissolved LWR fuel by tributylphosphate (TBP) and their subsequent sequential bwk-extraction from the TBP stream.
Date: January 1, 2001
Creator: Schroeder, N. C. (Norman C.); Attrep, Moses & Marrero, T. (Thomas)
Partner: UNT Libraries Government Documents Department

Integral measurements for higher actinides in CFRMF. [0. 1 to 2000 keV]

Description: To improve upon the lack of fast integral data for higher actinides, an effort is underway to measure integral capture and fission cross sections for /sup 242/Pu, /sup 241/Am and /sup 243/Am in the fast neutron zone of the Couple Fast Reactivity Measurements Facility (CFRMF). Fission cross sections are determined based on the Ge(Li) gamma spectrometric measurements of the absolute emission rates of the 537-keV and/or 1596-keV lines in the /sup 140/Ba - /sup 140/La decay. The capture rate for /sup 242/Pu is based on the measurement of the absolute emission rate of the 84.0 keV line in the /sup 243/Pu ..beta../sup -/ decay. Although the capture cross sections for /sup 241/Am and /sup 243/Am are not obtained directly, the cross sections for production of /sup 242/Cm and /sup 244/Cm are based on the quantitative alpha spectrometry and total alpha counting. Measured integral and capture cross sections for /sup 242/Pu are 357 mb +- 10% and 146 mb +- 15%. Corresponding spectral averaged cross sections calculated using ENDF/B-IV data and 489 mb and 238 mb, respectively. For /sup 241/Am fission and capture the measured cross sections are 504 mb +- 12% and 1.01 b +- 3%, respectively. For /sup 243/Am fission and capture, the measure cross sections are 0.352 b and .10 b, respectively. 19 references.
Date: January 1, 1979
Creator: Harker, Y.D.; Anderl, R.A.; Turk, E.H. & Schroeder, N.C.
Partner: UNT Libraries Government Documents Department

Experimental studies at the Idaho Chemical Processing Plant on actinide partitioning from acidic nuclear wastes

Description: Wastes generated at ICPP and in the reprocessing of LWR fuel is discussed separately. DHDECMP is used as extractant. Studies on DHDECMP purification and toxicity, diluent effects, reaction kinetics, radioloysis, mixer-settler performance, etc. are reported. 10 tables, 3 figures. (DLC)
Date: January 1, 1980
Creator: McIssaac, L.D.; Baker, J.D.; Meikrantz, D.H. & Schroeder, N.C.
Partner: UNT Libraries Government Documents Department

Separation of technetium from ruthenium after the accelerator transmutation of technetium

Description: Both civilian and defense related waste must be processed with a strategy for dealing with Tc. One solution is to remove the Tc from the waste steam and transmute the Tc to stable Ru in either a reactor or an accelerator. Before any processing of waste streams can be performed (even if transmutation is not performed) the separations chemistry from the spent fuels or the stored wastes containing Tc must be developed. This report details some of the separation schemes possible for the separation of Tc and Ru, which include the baseline ion exchange process of Roberts, Smith and Wheelwright, ozonolysis, filtration, magnetic separation, solvent extraction, electrodeposition, fluorination, and pyrolysis. 5 figs, 4 refs. (DLC)
Date: January 1, 1992
Creator: Abney, K.D.; Schroeder, N.C.; Kinkead, S.A. & Attrep, M. Jr.
Partner: UNT Libraries Government Documents Department

Fundamental chemistry, characterization, and separation of technetium complexes in Hanford waste. 1998 annual progress report

Description: 'The ultimate goal of this proposal is to separate technetium from Hanford tank waste. The recent work has shown that a large portion of the technetium is not pertechnetate (TcO{sub 4}{sup -}) and is not easily oxidized. This has serious repercussions for technetium partitioning schemes because they are designed to separate this chemical form. Rational attempts to oxidize these species to TcO{sub 4}{sup -} for processing or to separate the non-pertechnetate species themselves would be facilitated by knowing the identity of these complexes and understanding their fundamental chemistry. Tank characterization work has not yet identified any of the non-pertechnetate species. However, based on the types of ligands available and the redox conditions in the tank, a reasonable speculation can be made about the types of species that may be present. Thus, this proposal will synthesize and characterize the relevant model complexes of Tc(III), Tc(IV), and Tc(V) that may have formed under tank waste conditions. Once synthesized, these complexes will be used as standards for developing and characterizing the non-pertechnetate species in actual waste using instrumental techniques such as capillary electrophoresis electrospray mass spectrometry (CE-MS), x-ray absorbance spectroscopy (EXAFS and XANES), and multi-nuclear NMR (including {sup 99}Tc NMR). The authors study the redox chemistry of the technetium complexes so that more efficient and selective oxidative methods can be used to bring these species to TcO{sub 4}{sup -} for processing purposes. They will also study their ligand substitution chemistry which could be used to develop separation methods for non-pertechnetate species. Understanding the fundamental chemistry of these technetium complexes will enable technetium to be efficiently removed from the Hanford tank waste and help DOE to fulfill its remediation mission. This report summarizes the first 8 months of a 3-year project.'
Date: June 1, 1998
Creator: Schroeder, N.C.; Blanchard, D.L. Jr. & Ashley, K.R.
Partner: UNT Libraries Government Documents Department

Radionuclide separations using pillared layered materials

Description: This is the final report of a two-year Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Pillared Layered Materials (PLMs) are layered inorganic ion exchangers propped apart by metal oxide pillars. PLMs have been synthesized to sorb strontium from liquid nuclear wastes. A study that compared over 60 sorbers for their ability to sorb strontium from Hanford simulants showed that PLMs were the best sorbers; strontium distribution coefficients ({sup Sr}K{sub d}) > 20000 mL/g were obtained. In addition, PLMs showed a high degree of selectivity for strontium over cesium, transition metals, lanthanides and actinides. The sorption of strontium is, however, inhibited by complexants (EDTA); {sup Sr}K{sub d} values drop to <20 mL/g when they are present. The most promising PLMs were the Cr, Ti, Zr, and Si pillared tantalum tungstate. The K{sub d} values for Sr{sup 2+} and Ba{sup 2+} show a strong pH dependence; K{sub d} values increase to >10{sup 4} above pH 12. The general surface complexation mechanism explains the sorption of these cations on PLMs.
Date: December 31, 1998
Creator: Schroeder, N.C.; Wade, K.L. & Morgan, D.M.
Partner: UNT Libraries Government Documents Department

Preconcentration of low levels of americium and plutonium from waste waters by synthetic water-soluble metal-binding polymers with ultrafiltration

Description: A preconcentration approach to assist in the measurement of low levels of americium and plutonium in waste waters has been developed based on the concept of using water-soluble metal-binding polymers in combination with ultrafiltration. The method has been optimized to give over 90% recovery and accountability from actual waste water.
Date: December 31, 1997
Creator: Smith, B.F.; Gibson, R.R.; Jarvinen, G.D.; Robison, T.W.; Schroeder, N.C. & Stalnaker, N.D.
Partner: UNT Libraries Government Documents Department

Stabilization of Rocky Flats combustible residues contaminated with plutonium metal and organic solvents

Description: This report describes tests on a proposed flowsheet designed to stabilize combustible residues that were generated at the Rocky Flats Environmental Technology Site (RFETS) during the machining of plutonium metal. Combustible residues are essentially laboratory trash contaminated with halogenated organic solvents and plutonium metal. The proposed flowsheet, designed by RFETS, follows a glovebox procedure that includes (1) the sorting and shredding of materials, (2) a low temperature thermal desorption of solvents from the combustible materials, (3) an oxidation of plutonium metal with steam, and (4) packaging of the stabilized residues. The role of Los Alamos National Laboratory (LANL) in this study was to determine parameters for the low temperature thermal desorption and steam oxidation steps. Thermal desorption of carbon tetrachloride (CCl{sub 4}) was examined using a heated air stream on a Rocky Flats combustible residue surrogate contaminated with CCl{sub 4}. Three types of plutonium metal were oxidized with steam in a LANL glovebox to determine the effectiveness of this procedure for residue stabilization. The results from these LANL experiments are used to recommend parameters for the proposed RFETS stabilization flowsheet.
Date: September 30, 1998
Creator: Bowen, S.M.; Cisneros, M.R.; Jacobson, L.L.; Schroeder, N.C. & Ames, R.L.
Partner: UNT Libraries Government Documents Department

Evaluation of synthetic water-soluble metal-binding polymers with ultrafiltration for selective concentration of americium and plutonium

Description: Routine counting methods and ICP-MS are unable to directly measure the new US Department of Energy (DOE) regulatory level for discharge waters containing alpha-emitting radionuclides of 30 pCi/L total alpha or the 0.05 pCi/L regulatory level for Pu or Am activity required for surface waters at the Rocky Flats site by the State of Colorado. This inability indicates the need to develop rapid, reliable, and robust analytical techniques for measuring actinide metal ions, particularly americium and plutonium. Selective separation or preconcentration techniques would aid in this effort. Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively removing dilute actinide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for {sup 241}Am(III) and {sup 238}Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4.
Date: December 31, 1997
Creator: Smith, B.F.; Gibson, R.R.; Jarvinen, G.D.; Jones, M.M.; Lu, M.T.; Robison, T.W. et al.
Partner: UNT Libraries Government Documents Department