Use of alpha spectrometry for analysis of U-isotopes in some granite samples (original) (raw)
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Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015
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 St 4 (NMA). Several steps of sample preparation, radiochemical separation and source preparation were performed before analysis. Uranium was separated from sample matrix with 0.2 M TOPO in cyclohexane as an extracting agent with a chemical yield 98.95% then uranium was purified from lanthanides and actinides present with 0.2 M TOA in xylene as an extracting agent. The pure fraction was electrodeposited on a mirror-polished copper disc from buffer solution (NaHSO 4 þ H 2 SO 4 þ NH 4 OH). Rectangle pt-electrode with an anode-cathode distance of 2 cm was used. Current was 900 mA and the electrodeposition time reach up to 120 min. The achieved results show that the chemical yield ranged between 87.97 6.8 and 987 8.6.
Radioprotection, 2002
A new and accurate method for determination of uranium isotopes ( 238 U, 234 U and 235 U) in environmental samples by alpha spectrometry has been developed. Uranium is preconcentrated from filtered water samples by coprecipitation with iron (III) hydroxide at pH 9-10 using ammonia solution and the precipitate is dissolved with HN0 3 and mineralised with H 2 0 2 and HF; uranium in biological samples is ashed at 600 °C, leached out with Na 2 C0 3 solution and mineralised with HN0 3 , HF and H 2 0 2 ; uranium in soil samples is melted with Na 2 C0 3 and Na 2 0 2 at 600 °C and leached out with HC1, HN0 3 and HF. The mineralised or leaching solution in 2 M HN0 3 is passed through a Microthene-TOPO (trioctyl-phosphine oxide) column; after washing uranium is directly eluted into a cell with ammonium oxalate solution, electrodeposited on a stainless steel disk and measured by alpha spectrometry. The lower limits of detection of the method are 0.37 Bq kg" 1 (soil) and 0.22 mBq l" 1 (water) for 238 U and 234 U and 0.038 Bq kg" 1 (soil) and 0.022 mBq l" 1 (water) for 235 U if 0.5 g of soil and 1 litre of water are analysed. Five reference materials supplied by IAEA have been analysed and reliable results are obtained. The average uranium yields for waters, mosses, lichens and sediments are 74.5+9.0%, 80.5±8.3%, 77.8±4.9% and 89.4±9.7% respectively.
Determination of Uranium in Rocks and Soils of South Cameroon by γ-ray Spectrometry
RADIOISOTOPES, 2011
Analytical results of uranium concentration in rocks and soils collected in the area of Lolodorf of South Cameroon where a radiometric anomaly had been found by previous investigation are reported. The analysis has been carried out by γ-ray spectrometry using a detector. Radioactivity concentration of was determined by comparing peak count rates of samples with those of natural uranium standard sample. Radioactivity concentration of was calculated from the radioactivity concentration by assuming that the isotopic composition of is 0.7200 of natural abundance. Difference of γ-ray self-absorption between the samples and uranium standard was accurately corrected by using a mass attenuation coefficient of samples and standard measured by using an external γ-ray source. The radioactivity concentrations in rocks ranged from 0.92 0.02 to 228 14 and 20 5 to 4 868 307 , while radioactivity concentrations in soils ranged from 3 1 to 63 2 and 71± 19 to 1 346± 38 The γ-ray dose rates in air at 1 m above the ground surface due to the high uranium concentration in soil samples were ranged from 33± 9 to 622± 18. The highest uranium concentration of about 0.04 in rock was found in the analysis. These results show that the uranium content in the studied areas is significantly high and the studied areas have a potential for uranium mining.
THE 9TH INTERNATIONAL CONFERENCE OF THE INDONESIAN CHEMICAL SOCIETY ICICS 2021: Toward a Meaningful Society
The government of Indonesia plans to build a nuclear power plant (NPP). Prior to building the NPP, it is necessary to analyze the availability of uranium, the primary nuclear fuel, to develop a sustainable supply strategy. One type of uranium deposit in Indonesia is volcanic, associated with alkaline volcanic rocks. In nature, uranium isotopes are combined with other elements. Therefore, a good separation procedure is required to measure uranium concentration in a radioactive mineral exploration sample. We use standard reference material from the International Atomic Energy Agency and three volcanic rocks samples. First, dissolved samples were examined using a microwave digestion system with a mixed ratio of acid (HNO3, HCl, HF, and HClO4) to dissolve the sample. The next process involved separating the sample from its impurities using the extraction chromatography method by passing it into the UTEVA resin column with various flow rates. Furthermore, elution was examined to release the uranium bonds in the chromatography resin using various concentrations of HCl. In addition, uranium isotope concentrations were measured using ICP-MS. Chemical recovery of the proposed uranium measurement technique ranged from 90% to 96%. The proposed uranium measurement technique is useful for studying the existence of uranium that has undergone geochronological disequilibrium, rock weathering processes, and calculating the age of mineralization.
2020
Uranium is the most common element in the nuclear fuel cycle. Different techniques have been used for analyzing the isotopic composition of uranium. Precise determination of uranium isotopic ratios for an efficient control of nuclear material was carried out through the modification of the used chromatographic method of uranium. Alpha spectrometry was utilized to identify different types of natural, depleted and enriched samples for safeguard purposes. Uranium element was extracted from other interfering radionuclides, purified, electrodeposited on a stainless-steel disc, and measured using alpha-spectrometer, then isotopic ratios were calculated. For comparison purposes, the samples were also measured using a hyper pure germanium (HPGe) spectrometer and the uranium isotopic ratios were obtained. The results obtained by both techniques were in agreement within difference ranged from -8.7 to 12%. It was concluded that alpha spectrometric measurements of uranium isotopes preceded by e...
USE OF GAMMA-RAY SPECTROMETRY FOR URANIUM ISOTOPIC ANALYSIS IN ENVIRONMENTAL SAMPLES
Gamma-ray spectrometry was employed to determine the uranium isotopic ratios (235 U/ 238 U) in the environmental samples. A simple mathematical formula was derived and used to easily determine the 235 U in any environmental sample, regardless of 238 U equilibrium status. Also the adopted formula could be used for all types of environmental samples with different uranium isotopic ratios.
Journal of Radioanalytical and Nuclear Chemistry, 2010
During this work selective separation of uranium from rock phosphate and columbite mineral was done before its quantitative estimation by using Inductively Coupled Plasma Optical Emission Spectrometery (ICP-OES). Uranium from the rock phosphate and columubite was extracted by sodium peroxide fusion followed by leaching in 2 M HNO 3. To avoid spectral interference in the estimation of uranium by ICP-OES, the selective separation of uranium from the leachate was carried out by using two different extractants, 30% Tributyl Phophates (TBP) in CCl 4 and a equi-volume mixture of Di(2-ethylhexyl) phosphoric acid (D2EHPA) & TBP in petrofin. Uranium was stripped from the organic phase by using 1 M ammonium carbonate solution. Determination of uranium by ICP-OES was done after dissolving the residue left after evaporation of ammonium carbonate solution in 4% HNO 3. The concentration of the uranium observed in the rock phosphates samples was 40-200 lg g-1 whereas in columbite samples the concentration range was 100-600 lg g-1. Uranium concentration evaluated by ICP-OES was complimented by gamma & alpha spectrometry. Concentration of uranium evaluated by gamma spectrometry in case of rock phosphate and coulmbite was in close agreement with the uranium content obtained by ICP-OES. Uranium determination by alpha spectrometry showed only minor deviation (1-2%) from the results obtained by ICP-OES in case of rock phosphates whereas in case of coulmbites results are off by 20-30%.
Catalytic determination of traces of uranium in rocks by chronocoulometry
Electroanalysis, 1994
The chronocoulometric method for the determination of trace levels of uranium based on the catalytic reduction of nitrate, described in a preceding article, was applied and evaluated with real and synthetic samples. Samples with complex matrixes like rocks were first solubilized in hot acid (HF + HNO,) by digestion under pressure in a PTFE bomb. When necessary, liquid-liquid extraction with tri-n-butyl phosphate (TBP) followed by reversion to aqueous phase was used for previous separation of interferents. Results for a feldspar, a phosphorite, and three granitic rock samples, containing uranium in the range of 2 to 100 ppm, are in good agreement with those obtained by other techniques such as X-ray fluorescence, isotopic dilution-mass spectrometry (ID-MS), and instrumental activation analysis (differences of 4 to 16% in relation to the unweighted mean for different techniques).