Determination Of Uranium Isotopes Research Articles

Natural radionuclides in thermal mineral springs in Edipsos Greece.

Natural thermal and mineral therapeutic springs exist all over Greece. A radiological survey has been carried out in the municipality of Edipsos to study the naturally occurring alpha emitter radionuclides, 226Ra and the uranium isotopes. Thirteen thermal spring water samples and six tap water samples which were collected from five locations in the municipality of Edipsos, were analysed and measured by a-spectrometry. The obtained results show that 238U activity varies between 2.8±0.3 and 65.0±5.3 mBq/L in hot springs and between 2.70±0.35 and 10.6±0.9 mBq/L in tap water samples. The 234U/238U activity ratio lying between 1.12±0.17 and 2.12±0.30 indicates enrichment in the 234U concentration that can be explained through its ability to be easily leached from mineral surfaces. The 226Ra activity concentration varies between 3.5±0.4 and 1470±127 mBq/L in hot springs and between 6.5±0.9 and 28.2±2.8 mBq/L in tap water samples. Based on these results the estimated doses in this study are below the recommended dose of 1mSv/y. Highlights A radiological survey was carried out in the thermal springs of Edipsos, one of the most popular spa towns in Greece. Determination of uranium isotopes and 226Ra via a-spectrometry was performed. Low uranium content was a common characteristic for all the samples.

An innovative method for determination of uranium isotopes in soils by alpha-spectrometry coupled with Microthene-TOPO column separation

In the new procedure for determination of uranium isotopes by α-spectrometry, silica in the leachate of fused soil samples was coated with polyethylene glycol 2000 and eliminated through filtration, and uranium isotopes were separated from other α-emitters with a Microthene-TOPO column and electrodeposited on a stainless steel disc for measurement. It was observed that treatment with HF has negligible contribution on the release of uranium from the leachate containing silicates, so the use of HF for mineralization can be avoided. The reference material IAEA-315 marine sediment was analysed, and the obtained 238U, 234U and 235U concentrations are in good agreement with the certified values. The detection limit for soil samples was 0.23 Bq kg−1 for 238U or 234U and 0.08 Bq kg−1 for 235U if 0.5 g of samples were analysed. Method application shows that (1) the yields are high and stable, and (2) no interference from other α-emitters are observable in the final spectra.

Determination of uranium isotopes in marine sediments and seawaters by SF ICP-MS after rapid chemical separation using TK200 resin.

This work provided a novel analytical procedure for rapid and precise uranium isotopic determination in marine sediment and seawater, using a new type of extraction resin, TK200 resin, in combination with microwave digestion (for marine sediments), Fe(OH)3 co-precipitation (for seawater), and single collector sector field-inductively coupled plasma mass spectrometry (SF ICP-MS) measurement. The removal ability of TK200 extraction chromatography for the interfering elements (IEs) Hg, Pb, Th, Pt, Tl, and the matrix rare earth elements (REEs) was carefully investigated. High decontamination factors (DFs) were obtained for IEs and REEs. Accurate quantification of uranium isotope ratios was accomplished based on a "double-cycle" ICP-MS measurement method. The analytical method was optimized and validated with isotopic standards (IRMM-187), matrix-containing certified reference marine sediments (IAEA-384, IAEA-385, and IAEA-412), and seawater reference material (IAEA-443). A stable chemical recovery of ~ 90% was obtained for both types of marine environmental samples, and the method showed great efficiency with a total analytical time of less than 6h. The proposed procedure was validated following ISO/IEC 17025 guidelines. The important factors affecting the isotope ratio results (instrument background, procedural blank, memory effects, peak tailing, mass discrimination, dead time, and hydride interferences) were considered in the estimation of combined uncertainties. This work provides an alternative way for the determination of trace uranium isotope ratios and can be applied in the emergency monitoring of nuclear accidents and marine environmental analysis.

Determination of Uranium Isotopes in Environmental Samples Using Different Analytical Techniques: A Comparison

Determination of Uranium Isotopes in Environmental Samples Using Different Analytical Techniques: A Comparison

Rapid determination of uranium isotopes in calcium fluoride sludge by tandem quadrupole ICP-MS/MS

A rapid, novel and sensitive method was developed for the determination of uranium isotopes in CaF2sludge by using lithium metaborate fusion and ICP-MS/MS under He mode. This technology could be useful for treatment of radionuclide contaminated nuclear industry waste.

Изотопы урана в водах и льдах Памиро–Алая

The article presents the results of determination of concentration and isotope composition of uranium in waters and ice of the Pamiro-Alai. The obtained experimental data are the background for studying of the regularities of the formation of the effluent of mountain rivers. This work is significant because of the studied region is transboundary and is under the interest of the neighboring countries. Sampling was carried out during fieldwork in 2016 under the USAID-Afghanistan PEER454 project. Determination of uranium isotopes was carried out using high-resolution alpha-spectrometry after radiochemical isolation and purification. The main objects of this study are Kyzylsu and Muksu rivers with their tributaries, as well as the ice of this region. Three genetic types were determined based on the obtained experimental data. The first type includes atmospheric precipitations and young ice (ice from the glacier of Lenin and a spring near the Ters-Agar passage). The second type of water is characteristic for waters having contact with uranium-enriched rocks (the estuary of Kashkasu river). The third type of water is waters of deep circulation with active water exchange in mountain ranges with a high uranium concentration (eastern springhead of the Kyzylsu river). The calculations showed that the main source of most of the studied water bodies are atmospheric precipitations.

Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media

Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials.

Natural radioactivity content in groundwater of Mt. Etna’s eastern flank and gamma background of surrounding rocks.

<p>Waters of Mt. Etna are the main source of drinking water for the local population and are also distributed in municipal supply systems to neighbouring areas. Radioactivity in underground waters and surrounding rocks from the eastern flank of Mt.Etnawas investigated on the basis of 9 water and 8 rocks samples from 12 localities altogether. Three samples were from water drainage galleries and six from water wells. All water intakes are used for consumption. Activity concentration of uranium isotopes <sup>234,238</sup>U, radium isotopes <sup>226,228</sup>Ra and radon <sup>222</sup>Rn were determined with the use different nuclear spectrometry techniques. The determination of uranium isotopes was carried out with the use of alpha spectrometry. The measurements of radium and radon activity concentration in water were performed with the use of a liquid scintillation technique. Additionally, rocks surrounding the intakes were examined with gamma spectrometry. All water samples showed uranium concentration above Minimum Detectable Activity (MDA), with the highest total uranium (<sup>234</sup>U + <sup>238</sup>U) activity concentration equal to 149.2±6 mBq/L. Conversely, all samples showed radium isotopes activity concentrations below MDA. Radon activity concentration was within the range from 2.91±0.36 to 21.21±1.10 Bq/L, hence these waters can be classified as low – radon waters. Gamma natural background of the rocks surrounding the water sampling sites was found on the same levels as other volcanic rocks of Italy.</p>

Determination of uranium concentrations and 234U/238U activity ratio in some granitic rock samples by alpha spectrometry: Application of a radiochemical procedure

The present study is an application of a radiochemical procedure using alpha spectrometry technique for determination of uranium isotopes 238 U,234 U, and 235 U on 13 granitic samples. These samples were collected from Gabal Gattar area, Northeastern Desert, Egypt. The collected samples were digested using microwave technique with aqua regia and spiked with 232 U for chemical yield and activity calculation. Separation of uranium isotopes from the samples was done by Dowex 1 × 4 (50–100 mesh) resin followed by source preparation using microprecipitation technique. The concentrations of 238 U were ranged between 28.9 ± 0.9 and 134.8 ± 1.8 Bq/g, and the 234 U concentrations were between 24 ± 0.6 and 147.7 ± 2.2 Bq/g. For the 235 U, the activity concentrations were between 1.3 ± 0.2 and 6.7 ± 1.2 Bq/g. The activity ratio of 234 U/238 U was calculated and varied from 0.80 to 1.30.

Изотопы урана в водах хвостохранилища рудника Каджи-Сай

The paper presents the results of the determination of uranium isotopes in the water objects of the region Kadzhi-Sai, where former uranium mine, concentrating plant and tailing with a total volume of 400,000 m3 are located. Determination of uranium isotopes was done by alpha-spectrometry method with previous radiochemical preparation (coprecipitation on iron hydroxide, extraction with tributyl phosphate and electrodeposition on stainless steel disk) on alpha-spectrometer of «Canberra». On the basis of experimental data, the ratios of uranium-234 to uranium-238 were calculated, uranium isotope chart of determination of genetic composition of water were built and investigated. During the work three genetic types of waters were established: waters of deep circulation, waters of uranium anomalies draining tailing, and waters of active water exchange of the region. Their mixing proportions in the investigated water sources were calculated. It was found that drinking waters of Kadzhi-Sai village consist of only 5-7% of waters enriched by uranium; the major part (60-80%) is waters of deep circulation.

Accurate fast method with high chemical yield for determination of uranium isotopes (234U, 235U, 238U) in granitic samples using alpha spectroscopy

The present study aims to use the α-spectroscopy at Nuclear Materials Authority (NMA) of Egypt. A radiochemical technique for analysis uranium isotopes was carried out for ten mineralized granitic samples together with the International standards RGU-1 (IAEA) and St4 (NMA). Several steps of sample preparation, radiochemical separation and source preparation were performed before analysis. Uranium was separated from sample matrix with 0.2M TOPO in cyclohexane as an extracting agent with a chemical yield 98.95% then uranium was purified from lanthanides and actinides present with 0.2M TOA in xylene as an extracting agent. The pure fraction was electrodeposited on a mirror-polished copper disc from buffer solution (NaHSO4+H2SO4+NH4OH). Rectangle pt-electrode with an anode-cathode distance of 2cm was used. Current was 900mA and the electrodeposition time reach up to 120min. The achieved results show that the chemical yield ranged between 87.9±6.8 and 98±8.6.

Determination of 234U and 238U in seawater samples by alpha spectrometry after concentration of U(VI) onto hydrotalcite and co-precipitation with LaF3

Summary This paper presents a simple and accurate method for determination of uranium isotopes (234U and 238U) in seawater samples using alpha spectrometry. Uranium is pre-concentrated from seawater samples via adsorption on hydrotalcite at pH 6.5. The absorbent is dissolved into 50 ml of 8M HNO3; then filtered through a Dowex-1 column. U(VI) in the elution solution is reduced to U(IV) using zinc metal in 4M solution of HCl and then co-precipitated with LaF3. The chemical separation efficiency is found to be 97.12±2.68%, eliminating the need of using 232U tracer in other published methods. This method is validated via comparison with results obtained using inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA) for three seawater samples.

Novel method for determination of uranium isotopes in environmental samples by liquid–liquid extraction with triisooctylamine in sulfuric and hydrochloric acid media

Novel and robust method for determination of uranium isotopes in various environmental materials is presented. The method is based on total decomposition of the solid materials by the use of closed vessels microwave acid digestion systems and pre concentration of uranium from the liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid–liquid extraction with triisooctylamine/xylene in sulfuric and consecutively in hydrochloric acid media. Purified uranium is electrodeposited on a stainless steel disks and then measured by alpha spectrometry. The critical steps in the method were examined. The analytical method has been successfully applied to the determination of uranium isotopes in mineral and tap waters, as well as in soils from Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices.

Determination of uranium isotope ratios in human urine by sector field inductively coupled plasma mass spectrometry for use in occupational and biomonitoring studies

Determination of uranium isotopes in urine is critical for distinguishing between exposure to natural and anthropogenic sources of uranium. In biomonitoring, the extremely low levels of total uranium [U] present in urine and the complexity of the urine matrix present challenges to accurate isotope ratio determination. We have validated a method for measurement of 234U/238U, 235U/238U and 236U/238U in small-volume, random urine samples at occupational exposure levels, as well as for measurement of 235U/238U at biomonitoring levels. The method has been developed to detect exposure to mixtures of enriched and depleted uranium (DU) among former workers and nearby residents of the NL Industries factory in Colonie, NY, USA. Validation experiments employing solid phase extraction followed by SF-ICP-MS analysis were performed on base urine spiked with isotopic certified reference materials, isotopically depleted urine quality control materials, and natural uranium urine pools. Our results show that extraction with UTEVA resin yields lower blank levels than with TRU resin, and that double washing of the UTEVA resin columns results in further lowering of the blank. At occupational exposure levels ([U] = 50 ng L−1), 234U/238U, 235U/238U, and 236U/238U can be quantified in 1 mL of urine containing 3% DU with relative precisions (1s) of 10%, 0.4%, and 18%, respectively. For urine containing 75% DU and [U] = 50 ng L−1, the relative precision (1s) of 236U/238U is improved to <3%. At biomonitoring levels ([U] = 5 ng L−1), by increasing the urine volume to 4 mL, 234U/238U and 235U/238U can be quantified with relative precisions (1s) of 19% and 0.5%, respectively, whereas 236U/238U cannot be detected. By further increasing urine volume to 8 mL, comparable levels of isotope ratio precision are possible at [U] as low as 1 ng L−1.

Determination of uranium, thorium and plutonium isotopes by ICP-MS

Quantitative and isotopic measurement of actinide elements is required in many circumstances in the nuclear industry. For example, determination of very low levels of these alpha emitters in human urine samples is used to assess the internal committed dose for nuclear workers. Quantifying actinide isotopes in radioactive waste from nuclear processing and nuclear facility decommissioning provides important information for waste management. Accurate determination of the uranium isotopic ratios in reactor fuels provides fuel burnup information. Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of Th, U, and Pu in various samples including urine, nuclear waste, and nuclear fuel in our laboratory. In order to maximize the capability of the technique and ensure quality analyses, ICP-MS was used to analyze samples directly, or after pre-treatment to separate complicated matrices or to concentrate the analyte(s). High-efficiency sample introduction techniques were investigated. Spectral interferences to minor isotopes caused by peak tails and hydride ions of major actinide isotopes were studied in detail using solutions prepared with light and heavy waters. The quality of the isotopic ratio measurement was monitored using standard reference materials.

Determination of uranium isotopes in environmental samples

The determination of isotopes of uranium by alpha spectrometry in different environmental components (sediments, soil, water, plants and phosphogypsum) is presented and discussed in this paper. The alpha spectrometry is a very convenient and good technique for activity concentration of natural uranium isotopes (234U, 235U, 238U) in environmental samples and provides the most accurate determination of isotopic activity ratios between 234U and 238U. The analysis were provided information about possible sources of high concentrations of uranium in the examined sites determined by anthropogenic sources. The calculation of values 234U/238U in all analyzed samples was applied to identifying natural or anthropogenic uranium origin. Activity concentration of uranium isotopes in analyzed environmental samples shows that measurement of uranium levels is of great importance for environmental and safety assessment especially in contaminated areas (phosphogypsum waste heap).

Method for determination of uranium isotopes in environmental samples by liquid–liquid extraction with triisooctylamine/xylene in hydrochloric media and alpha spectrometry

Alternative method for determination of uranium isotopes in various environmental samples is presented. The method is based on total decomposition of the solid materials and preconcentration of liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid–liquid extraction with triisooctylamine/xylene in hydrochloric media. After the additional removal of stable iron by extraction with diisopropyl ether, purified uranium is electrodeposited on stainless steel disks and measured by alpha spectrometry. The analytical method has been successfully applied to the determination of uranium isotopes in water and bottom sediments from the rivers Danube, Ogosta and Tzibritza in Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices.

Determination of uranium isotopes in irradiated thorium dioxide by alpha spectrometry using WinALPHA for deconvolution of complex spectra

Isotopic composition of uranium obtained from irradiated thorium dioxide was determined using alpha spectrometry by employing WinALPHA for the deconvolution of the alpha spectra recorded using electrodeposited sources. The results obtained were found to agree within 1% with those determined by thermal ionization mass spectrometry. The deconvolution methodology is important since it is possible to account for the in-growth of 228Th, which interferes in the determination of 232U by alpha spectrometry. The present methodology has the potential to determine isotopic composition of uranium in the irradiated thorium based nuclear fuels, employing alpha spectrometry.

Validation of isotopic analysis of depleted, natural and enriched uranium using high resolution ICP-OES

Analytical procedures for the reliable determination of uranium isotopes employing a commercially available high resolution (HR)-ICP-OES installed in a glove box were developed and validated. To this end, nine commonly used U emission lines were tested for their potential to provide isotopic splitting of the U signal, thus providing isotopic information. Among all emission lines tested, the wavelength region around 424.4 nm offered the largest spread between individual U signals, i.e.233U, 235U, 236U, and 238U. This study focused specifically on the reliable determination of the abundances of 235U at 424.412 nm and 238U at 424.437 nm in samples containing depleted, natural and slightly enriched U, but also included specimens with rather high (up to ∼90%) 235U enrichments. Appropriate selection of the spectral background and accurate positioning of the peaks proved essential for obtaining reproducible U isotope ratios. The accuracy of the developed methodology was confirmed by the analysis of eight certified isotopic reference materials as well as eight reference samples that have been characterised in an accredited laboratory in-house using TIMS. In addition, this study highlights the potential of the developed HR-ICP-OES procedure for identifying nuclear sources of various U specimens via the analysis of 233U (424.398 nm) and 236U (424.423 nm). In contrast to the commonly used techniques, the methodology applied in this study does neither require the separation of U from the matrix prior to analysis nor the regular analysis of a reference sample with a known isotopic composition to correct for bias effects as it is the case for more sophisticated and precise mass spectrometric measurements. Nevertheless, HR-ICP-OES provides fit for purpose U isotopic information with reasonable accuracy (typically <1.5%) and precision (∼1%) within a few minutes. As such, HR-ICP-OES can be employed as a reliable, fast screening tool to identify the U isotopic composition and as such, complements the more laborious TIMS analysis routinely employed for this purpose.

Uranium determination in water samples with elevated salinity from Southern Poland by micro coprecipitation using alpha spectrometry

Due to the importance of water in human life, its quality must be strictly controlled; so simple and reliable analytical methods must be available. For this purpose a rapid procedure for the determination of uranium isotopes in natural water samples with elevated salinity was adopted. It was tested in 16 water samples from Upper and Lower Silesia Regions in Poland. Water samples had salinity in a range of 290–26,925 mg l − 1 . In water samples the concentrations of 234U and 238U ranged from 2.07 to 52.08 mBq l – 1 and from 2.18 to 43.38 mBq l – 1 respectively, while 235U level was below MDA (0.7 mBq l − 1 ). The isotopic ratio of 234U/ 238U varies in the range from 0.949 to 3.344 in all investigated waters which means that there is usually no radioactive equilibrium between the parent nuclide 238U and its daughter product 234U. These results do not show a correlation between total dissolved solids (TDS) values and concentration of dissolved uranium isotopes. Committed effective dose for adults due to uranium intake as a result of drinking water usage was in range of 0.15–3.29 µSv y − 1 with an average value of 1.09 µSv y − 1 far below the 100 µSv y − 1 WHO recommendation.