bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiochemical neutron activation analysis of total trace tin and determination of its differentiated compounds in aquatic biota
Authors: Amer H. A. , Shawky S. 
Published: September 2005

Summary
The optimization of extraction and determination of trace tin using radiochemical neutron activation analysis (RNAA) in selected aquatic specimen (algae, fish, mussels) is described. Neutron activation analysis (NAA) using the induced 117mSn (13.6 days) or 113Sn (115 day) nuclides is in principle a sensitive method for determination of total trace tin. However, due to the high contents of arsenic (As) in most marine matrices, neutron irradiation induces high levels of 76As (26.3 h) in comparison to weak 117mSn activities. Selective removal of As by absorption on Acidic Aluminum Oxide (AAO) would be advantageous and reduce the activities required to be handled during tin purification. It was found that perchloric acid medium is the best eluent for separating Sn from As, whereas sulfuric acid and a mixture of the two were not as effective. The standard radiochemical separation procedure based on solvent extraction and purification of tin iodide in toluene from sulfuric acid-potassium iodide (KI) medium with recoveries ranging between 90%–95% is applied. Interferences from the 47Ca/47Sc decay and 199Au with similar gamma energies were effectively removed by the liquid/liquid separation. Comparing the total tin content in freeze-dried samples with the total organotin content in fresh samples shows that the drying process has changed the tin species pattern of the material. The total butyltin content represents 60% and 90% of the total tin content in eel-pout and bream muscles, while it represents about 76%–83% and 58%–88% in mussels and algae, respectively.
Production and radiochemical separation of rhodium-105 for radiopharmaceutical applications
Authors: Unni P. R. , Pillai M.R.A. 
Published: September 2005

SummaryProduction of no carrier added105Rh by thermal neutron irradiation of natural Ru target and ist radiochemical separation to obtain radionuclidically and radiochemically pure species is described. Irradiation planning, post irradiation chemical separation of105Rh from ruthenium and irridium radionuclidic contaminants are discussed in detail. 100 mg of natural Ru was irradiated in a thermal neutron flux of 3 × 1013 neutrons/cm2/s for 7 days. Irradiated target was disolved in an mixture of KIO4and KOH in presence of water. Solvent extraction with CCI4was used for removal of97Ru and103Ru, whereas solvent extraction with TBP was used for the removal of traces of192Ir impurity. Different radiochemical separation techniques were tested for the recovery of105Ru and ist final purification from the accompanying radionuclidic impurities. The salts associated with the product were subsequently removed by fractional precipitation and by cation exchange chromatography. The radionuclidic purity of the105Rh separated was estimated by gamma ray spectrometry; no radionuclidic contamination was observed. The radiochemical purity of the105RhCI3was acsertained bx paper chromatography and paper electrophoresis. Production of no carrier added105Rh by thermal neutron irradiation of natural Ru target and ist radiochemical separation to obtain radionuclidically and radiochemically pure species is described. Irradiation planning, post irradiation chemical separation of105Rh from ruthenium and irridium radionuclidic contaminants are discussed in detail. 100 mg of natural Ru was irradiated in a thermal neutron flux of 3 x 1013 neutrons / cm2/ s for 7 days. Irradiated target was disolved in an mixture of KIO4and KOH in presence of water. Solvent extraction with CCI4was used for removal of97Ru and103Ru, whereas solvent extraction with TBP was used for the removal of traces of192Ir impurity. Different radiochemical separation techniques were tested for the recovery of105Ru and ist final purification from the accompanying radionuclidic impurities. The salts associated with the product were subsequently removed by fractional precipitation and by cation exchange chromatography. The radionuclidic purity of the105Rh separated was estimated by gamma ray spectrometry; no radionuclidic contamination was observed. The radiochemical purity of the105RhCI3was acsertained bx paper chromatography and paper electrophoresis.
Transmutation of239Pu and other nuclides using spallation neutrons produced by relativistic protons reacting with massive U- and Pb-targets
Authors: Brandt R. , Westmeier Wolfram , Odoj R. , Adam J. , Adloff J. C. , Balabekyan A. , Barabanov M. Y. , Bradnova V. , Chaloun P. , Debeauvais M. 
Published: September 2005

SummaryExperimental studies on the transmutation of some long-lived radioactive waste nuclei, such as129I,237Np, and239Pu, as well as on natural uranium and lanthanum were carried out at the Synchrophastron of the Laboratory for High Energies at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The radioactive targets (I, Np and Pu) were contained in weld-sealed aluminium holders produced by the Institute of Physics and Power Engineering, Obninsk, Russia. Spallation neutrons were produced by relativistic protons with energies in the range of 0.5 GeV≤Ep≤1.5 GeV interacting with 20 cm long uranium or lead target stacks. The metallic targets were surrounded by 6 cm thick paraffin moderators. The uranium and lanthanum samples were positioned on the outside of the moderator surface and typically contained approximately 0.5 to 1.0 gram of uranium or lanthanum. The highest fluence of spallation neutrons was observed in the region of 5 to 10 cm downstream the entrance of the primary beam into the metallic target, rather independent of the target material or the proton energy. The results obtained by nuclear chemistry methods were supplemented by SSNTD (Solid State Nuclear Track Detector) studies. Consistent and systematic results ofB-values and spectral distributions for neutrons have been found. From the experimentally observed transmutation rates one can extrapolate that in a subcritical nuclear power assembly (or "energy amplifier") using a 10 mA proton beam of 1 GeV onto a Pb-target as used here, one can transmute within one month in one gram of sample about 3 mg129I, 21 mg237Np, 3.3 mg238U, and 200 mg239Pu. Rather similar results have been found by another group for129I and239Pu. Observations show that the transmutation rates increase almost linearly with the proton energy in the energy interval 0.5 GeV up to 7.4 GeV. These findings are largely confirmed by model calculations using the LAHET- and DCM/CEM-codes.
Sample preparation methods for the determination of plutonium and strontium in environmental samples by low level liquid scintillation counting and α-spectrometry
Authors: Solatie D. , Carbol P. , Hrnecek E. , Jaakkola T. , Betti M. 
Published: September 2005

SummaryTwo different methods – leaching and microwave assisted total dissolution – have been exploited for the treatment of environmental samples for the determination of plutonium and strontium. Leaching applied to reference materials demonstrated the procedure to be applicable for the recovery of technogenic Pu and Sr from environmental samples.For the measurement of the alpha emitters of plutonium, co-precipitation with calcium oxalate and ferric hydroxide and separation with anion exchange has been used. For preparation of α-spectrometry sources, co-precipitation with NdF3on a membrane filter or electro-deposition using the (NH4)2C2O4/HCl method have been tested. The beta emitter241Pu was measured by liquid scintillation counting. Pu isotope concentrations determined in the reference materials agreed well with the certified concentrations.90Sr was measured in the leachate solutions from environmental samples collected close to a nuclear facility and from reference materials, after separation from the other leached elements, by liquid scintillation counting and Cherenkov counting. The90Sr-concentrations determined in the reference materials agreed well with the certified concentrations. In the samples collected close a nuclear facility (soil, grass and sheep faeces),90Sr was found at higher levels, which could also be correlated with the location of the sampling.
Studies on the extraction of uranium by N-octanoyl-N-phenylhydroxamic acid
Authors: Saha B. , Venkatesan K. A. , Natarajan R. , Antony M. P. , Vasudeva Rao P. R. 
Published: September 2005

Summary
N-octanoyl-N-phenylhydroxamic acid (OHA) has been prepared by partial reduction of nitrobenzene with Zn dust/NH4Cl, followed by acylation with n-octanoyl chloride. Structure of OHA was confirmed by 1H NMR, IR spectra and CHNS microanalysis. The extraction of uranium by OHA has been studied as a function of pH, temperature and concentration of OHA. The extraction of uranium was found to increase with increase in pH. Uranium forms a 1:2 complex with OHA. IR Spectra & NMR Spectra of the uranium-OHA complex and slope analysis obtained from extraction studies indicated that the extraction of uranium was due to the formation of a chelate. The enthalpy change accompanied by the extraction of uranium by OHA has been obtained by temperature variation method. The extraction process was found to be endothermic at pH 2 and exothermic at pH 6.
Transport of U(VI), Th(IV) and lanthanides through cation exchange membrane impregnated with HDEHP-kerosene using electric field
Authors: Gasser M. S. , Zaki E. E. 
Published: September 2005

Summary
Electrodialysis has been investigated as a method to enhance the transport of U(VI), Th(IV) and lanthanides through Nafion cation exchange membrane I and impregnated with HDEHP-kerosene II. The recovery factor of U(VI) through Nafion cation exchange membrane with and without the applied electric field was 0.8 and 0.14, respectively. The transport process of U(VI) through ion exchange membrane was studied as a function of variation of nitric acid concentration in the feed solution, HDEHP concentration in the membrane stripping solution concentration, pH of the feed solution and effect of electric field. From this study the cationic flux of U(VI) through Nafion I and impregnated with HDEHP-kerosene II was 5.2 × 10−8 and 8.7 × 10−8 g eq cm−1, respectively. The technique of electrodialysis is efficient in preconcentration of U(VI) to 2.8 fold of the initial concentration. The recovery factors of lanthanide elements La(III), Eu(III) and Er(III) through the systems I and II were 0.8 in system I and 0.86, 0.8 and 0.73 in system II, respectively. The recovery factors of La(III), Eu(III), Er(III) and U(VI) through the system II were 0.82, 0.75, 0.71 and 0.27, respectively. The recovery factor of Th(IV) and U(VI) at pH = 1.5 was found to be 0.99 and 0.3, respectively.
Partial and total thermal neutron capture cross sections for non-destructive assay and transmutation monitoring of 99Tc
Authors: Molnár G. L. , Belgya T. , Révay Zs. , Qaim Syed M. 
Published: September 2005

Summary
Accurate partial gamma-ray production cross sections were determined for the prompt and radioactive product decay gamma rays following cold neutron capture in 99Tc. They can be used for non-destructive assay of technetium by prompt gamma activation analysis (PGAA) and neutron activation analysis (NAA), offering orders of magnitude higher analytical sensitivities than passive gamma-ray counting. A lower limit of 21.21 ± 0.17 b was also deduced for the thermal-neutron-capture cross section.
Control of plutonium dioxide solubility by amorphous tetrahydroxide: A critical review of the model
Authors: Haschke J. M. , Bassett R. L. 
Published: September 2005

SummarySolubility data for dissolution of plutonium dioxide and tetrahydroxide in laboratory and natural waters are compared with results of modeling calculations. Evaluation shows that selection of metastable Pu(OH)4as the solubility-controlling solid results in predicted steady-state plutonium concentrations that are not conservative and oxidation-state distributions that are inconsistent with observation. Although only the presence of Pu(III) and Pu(IV) is predicted at measured solution potentials, Pu(V) and Pu(VI) predominate (>95%) in steady-state solutions at pH 1–9. Behavior is inconsistent with thermodynamic and kinetic constraints of the conceptual chemical model and a strong dependence of experimental equilibrium expressions on the amount of solid hydroxide in the steady-state solution suggests that dissolution of plutonium oxide is not an equilibrium process.
Technetium migration in fluoroapatite during thermal annealing
Authors: Gaillard C. , Chevarier N. , Millard-Pinard N. 
Published: September 2005

SummaryTechnetium migration was investigated apatite a possible nuclear wastes conditioning materials.99mTc was introduced into fluoroapatite by ion implantation. The analysis of implanted profile evolution under samples treatment allows to identify the migration process as a bulk diffusion. The observed Tc release is correlated to the oxidation of Tc by interaction with air at the sample surface.
Uranium release from boom clay in bicarbonate media
Authors: Wang L. , Dierckx A. , De Cannière P. , Maes A. 
Published: September 2005

SummaryThe release of natural uranium from Boom Clay was studied to better understand the mechanisms governing the solid-liquid partitioning of uranium. Batch leaching experiments suggested that the portion of natural uranium released from clay is associated with colloids at a low bicarbonate concentration prevailing in Boom Clay. At increased bicarbonate concentrations, uranium was present predominantly as dissolved species indicating a formation of uranium carbonate complexes. Thein situaqueous uranium concentration,i.e., the concentration in the pore waters collected by piezometers was found to be 2 to 3 orders of magnitudes lower than the one measured by the batch techniques. These results illustrated that the batch techniques may cause a remobilization of uranium containing colloids from clay surfaces into solution when clay is suspended, agitated, and mechanically perturbed. These colloids are attributed to artefacts and are not considered to existin situbecause of the high compaction of Boom Clay. Due to the presence of colloids, a laboratory derived solid-liquid partitioning coefficient is not equivalent to and cannot simply be converted to the distribution coefficientKdcurrently used in performance assessment calculations.
Formation of secondary phases after long-term corrosion of simulated HLW glass in brine solutions at 190 °C
Authors: Zimmer P. , Bohnert E. , Bosbach Dirk , Kim Jae-Il , Althaus E. 
Published: September 2005

SummaryThe behavior of rare earth elements (REE) as chemical analogues for actinides during glass corrosion was studied with static long-term batch experiments (7.5 years) at 190 °C. Corrosion tests were carried out using a simulated inactive high level waste (HLW) glass powder. Two different highly concentrated salt solutions (NaCl-rich and MgCl2-rich) have been used to simulate the potential corrosion by aqueous solutions in geological salt formations. Samples with surface-to-volume ratios (S/V) of 1000 m−1and 10000 m−1were investigated. The chemical composition of the aqueous solution and the formation of secondary phases at the glass/solution interface as well as their elemental composition, especially with respect to the behavior of REE was studied. The glass corrosion behavior and secondary phase formation was significantly different in the two brines. In the MgCl2-rich salt solution, with a final pH < 3.5, hydrous Mg-silicates and (Ba,Sr)SO4solid solutions with considerable amounts of Sr (up to 15 wt.%) have been observed. Further, REE-sulfates and REE-molybdates with an indication of dissolution (etch pits) as secondary phases could be identified. In the NaCl-rich solution with a final high pH, REE-containing hydrous silicates (up to 35 wt.%) and (Ba,Sr)SO4solid solutions with small amounts of Ce (up to 5 wt.%) have been observed. Frequently observed Ca-molybdates (powellite) did not contain detectable amounts of REE.
Sorption behaviour of Am on precorroded HLW glass in water and brines
Authors: Luckscheiter B. , Nesovic M. 
Published: September 2005

Summary
In the alteration layer of HLW glasses corroded in aqueous solutions, less soluble elements like REE, actinides and other elements are retained by sorption or by formation of secondary alteration products controlling the solution concentrations. In order to quantify the sorption effect on the retention of metal ions, first sorption tests with U, Th and Eu have been performed using precorroded, simulated HLW glass as substrate.
To demonstrate that the sorption behaviour of Eu is also representative for homologue trivalent actinides additional sorption tests were performed with Am241 in deionized water, NaCl and MgCl2 brine. Distribution ratios R
s (R
s=Amsorb/ Amsol× V/m) for Am were found independent of the starting concentration in the pH range 2 to 6. At higher pH, a high amount of Am-containing colloidal particles were detected. The R
s values of Am show a strong increase with pH, quite similar to the R
s values of Eu. In general, the sorption behaviour of Eu and Am is very similar in deionized water and in brines. Clay minerals formed in the gel layer as secondary phases during long-term glass corrosion are assumed to act primilary as strong sorbents. Therefore, the sorption of REE and Am onto synthetic poor crystalline smectite precursors and a "well crystallized" natural smectite is compared with the findings obtained from precorroded glass. The sorption of Am on the precorroded glass is found to be much stronger than the retention on the investigated pure clay phases, indicating a different number of active sites or occurance of a different sorption mechanism.
Molecular fluorescence spectroscopy and mixture analysis for the evaluation of the complexation between humic acid and UO2
2+
Authors: Saito Takumi , Nagasaki S. , Tanaka S. 
Published: September 2005

Summary
Humic acid (HA) was fractionated by gel permeation chromatography and the complexation of the obtained three fractions with UO2
2+ was examined by synchronous fluorescence spectroscopy combined with SIMPLISMA, which is one of the mixture analysis methods. Most of the fluorescence of HA resulted from the lowest molecular weight fraction, and the quenching behavior of this fraction was similar to that of unfractionated HA. After the spectral resolution by SIMPLISMA, two components, which were differently quenched with UO2
2+, were extracted for both cases. The complexing parameters, the apparent stability constant and the concentration of complexing sites, were evaluated for each component and compared between unfractionated HA and the lowest molecular weight fraction.
Investigation on uranyl interaction with bioactive ligands. Synthesis and structural studies of the uranyl complexes with glycine and N-(2-mercaptopropionyl)glycine
Authors: Keramidas A. D. , Rikkou M. P. , Drouza C. , Raptopoulou C.P. , Terzis A. , Pashalidis I. 
Published: September 2005

Summary
Three new uranium(VI) compounds have been prepared with glycine (Hgly), N-(2-mercaptopropionyl)glycine (Hmpg) and 2,2′-dithiobis(N-propionylglycine) (tpg). The crystal structure of [UO2(Hgly)2Cl2] has been solved, revealing the uranium atom to be seven-co-ordinated. The two zwitterionic glycines are coordinated to uranium atom by the carboxylate groups, one in a monodentate and the other in a bidentate mode. Solid state studies and low temperature 1H, 13C, 2D COSY and HMQC solution NMR spectra of the [UO2(mpg)(CH3COO)], show that mpg coordinates uranium atom by the carboxylate group.
Complex formation of Eu(III) with humic acid and polyacrylic acid
Authors: Kubota Takumi , Tochiyama Osamu , Tanaka K. , Niibori Yuichi 
Published: September 2005

SummaryWith the intention of estimating the effect of the heterogeneous composition in the humic acid separately from its polyelectrolyte effect, comparative study on the interaction of Eu(III) with humic acid and polyacrylic acid has been carried out by the solvent extraction method with 10−3M TTA and 10−3M TBP in xylene at various total concentrations of Eu(III) (10−8M to 10−5M), pcH(5.0 to 5.5) and ionic strengths (0.02 to 1.0 M NaClO4). The interaction has been discussed in terms of the apparent complex formation constants, βα= [ML]/([M][R]), where [M] and [ML] are the concentrations of free and bound Eu3+ion and [R] is the concentration of dissociated proton exchanging site. For both humate and polyacrylate, logβαincreased with pcHor the degree of ionization and decreased with ionic strength. The Eu3+ion concentration had no appreciable influence on the complex formation of Eu(III)-polyacrylate, and the values of logβαwere obtained to be 7.57 ± 0.05 (I= 0.1, pcH= 5.53), 7.13 ± 0.04 (I= 0.1, pcH= 5.20), 6.68 ± 0.04 (I= 1.0, pcH= 5.54) and 5.61 ± 0.09 (I= 1.0, pcH= 4.73). On the other hand, logβαof humate remarkably decreased with the Eu3+ion concentration; from 9.32 ([Eu3+] = 10−11.9M) to 7.20 ([Eu3+] = 10−7.5M) at pcH= 5.53 in 0.02 M NaClO4, from 8.63 ([Eu3+] = 10−12.5M) to 6.35 ([Eu3+] = 10−7.2M) at pcH= 5.53 in 0.1 M and from 7.59 ([Eu3+] = 10−10.7M) to 5.20 ([Eu3+] = 10−7.0M) at pcH= 5.52 in 1.0 M. The observed dependence of logβαof humate on the concentration of metal ion strongly suggests the heterogeneity of the complexing sites (the coexistence of weak and strong binding sites) in the humic acid.
XAS study of technetium(IV) polymer formation in mixed sulphate/chloride media
Authors: Vichot L. , Ouvrard G. , Montavon G. , Fattahi Massoud , Musikas C. , Grambow Bernd 
Published: September 2005

SummaryX-ray absorption spectroscopy has been used to establish polymer formation of Tc(IV) in aqueous solutions of Na+SO42−and Na+Cl−/SO42−.As the molybdenum chemistry show similarities to that of technetium, we used MoO2as a reference to model our technetium species. Fitting of TcO2·xH2O with this model led to a good correlation with the literature data: (Tc-Tc=2.53 Å, Tc-O=1.87-1.98 Å).In aqueous solution, some polymers are formed regardless to the nature of the media composition: Tc-Tc=2.50 ± 0.02 Å. The general structure is in agreement with a first coordination shell containing 6 O. The modelling shows that, in the first coordination shell, there is no chloride ligand. The observed geometries are close to those found for TcO2·xH2O, hence the unknown aqueous species must be considered as a precursor of the solid technetium dioxide.Combination of these results with XANES led to attribute TcnIVOp(4n-2p)+(H2O)qwith n>2 to the species.