Determination Of Uranium In Solutions Research Articles

Determination of uranium in solutions by the neutron activation analysis method with 252Cf radionuclide neutron source

A determination option for 238U in solutions by the neutron activation analysis was investigated. A radionuclide treatment based on 252Cf was used as a neutron source. The limit for the determination of uranium using thermal neutrons of 0.1 mgL?1 was determined within the research framework. With the help of the preliminary concentration of the sample via the evaporation method, it is possible to further reduce the detection limit by 2-5 times. It is defined that the optimal time for measuring the induced activity of the sample when working with a short-life isotope of 239U, is 30 minutes. The influence of the effects of scattering and self-absorption of gamma radiation of the uranium line 74.6 keV on the results of the neutron activation analysis was determined. The studies conducted made it possible to determine uranium by the neutron activation analysis method in solutions of various compositions, in a wide range of concentrations.

Comparison of fluorescence-enhancing reagents and optimization of laser fluorimetric technique for the determination of dissolved uranium

Results from tests aimed at optimizing an instrumental procedure for the direct and fast determination of uranium in solution by laser fluorescence are presented. A comparison of sample fluorescence measured using different fluorescence enhancing reagents was performed: sodium pyrophosphate, orthophosphoric acid, sulphuric acid and a commercially available fluorescence enhancer were tested for the determination of uranium. From the experimental results, 0.01 M Na4P2O7·10H2O showed the best performance. Effects of reagent pH, different matrices, different concentrations of dissolved Th, and sample volume were investigated. Applications of the improved procedure for the determination of uranium in samples arising from UO2-based high level nuclear waste dissolution studies are described.

X-ray spectrometric method for the determination of uranium in solution by a cellulose disc technique

An X-ray fluorescence spectrometric method is described for the determination of uranium in liquid samples by absorbing drops of solution on cellulose discs. Internal standards thorium, strontium or yttrium are added in the uranium solution to follow the non-uniform absorption of the liquid on the disc. A precision of better than ±0.5% is obtained for uranium determination with all the three internal standards. The method was also employed to determine uranium in the presence of plutonium and americium without any interference effects.

Determination of uranium in solutions and sorbents by soft gamma-ray absorptiometry

The determination of uranium in solutions and sorbents by measurement of absorption of soft gamma-rays is described. The use of 22 keV gamma-rays of109Cd enbled us to improve the sensitivity of the determination for nearly an order of magnitude when compared to the measurements using241Am source. The application to the continuous measurement of uranium concentration in pilot-plant streams and of concentration profiles of uranium sorbed on columns of ion exchangers is described.

Determination of uranium in solution at the ng 1 −1 level by time-resolved laser-induced spectrofluorimetry: application to geological samples

Time-resolved laser-induced spectrofluorimetry was used for the determination of uranium at the ng 1 −1 level in alkaline water with high chloride and sulphide contents in order to obtain a better understanding of uranium mobilization under natural reducing conditions. The optimum complexing medium, limit of detection and results obtained for several waters from different localities in the Pyrenees are presented. These data seem to confirm that even at very low uranium concentrations, thermodynamic control by a mineral phase takes place.

Determination of Uranium in Solution Using Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy was used to determine uranium in solution for possible application to process control in nuclear fuel reprocessing facilities. Pulses from a Nd: YAG laser were focused on the surfaces of the liquids in order to generate the sparks. The spark light was spectrally resolved and detected with the use of a time-gated photodiode array. The detection limit for uranium in 4 molar nitric acid was 0.1 g/L. Measurement precisions were 1–2% for a 4.2-g/L solution with the use of 1600 laser sparks, corresponding to a measurement time of about three minutes. A calibration curve was prepared that spanned uranium concentrations from 0.1 to 300 g/L. The effects of some experimental parameters on the analysis are discussed.

Determination of uranium in a kerosene solution of organophosphorus extractants

A back-extraction (stripping) procedure, combined with two spectrophotometric methods, has been developed for the determination of uranium in kerosene solution. Uranium(VI) is stripped from a kerosene solution of organophosphorus extractants with sodium carbonate solution and, after a subsequent reaction with 4-(2-pyridylazo)resorcinol or 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (as chromogenic reagents) is determined spectrophotometrically. These reagents are highly sensitive and form stable complexes with uranium. The procedure has been successfully applied to the determination of uranium in solutions of organophosphorus extractants in real systems, i.e., during the extraction of uranium from wet-process phosphoric acid.

Determination of uranium in ores and in solution using a portable non-dispersive X-ray spectrograph

The portable non-dispersive X-ray fluorescence instrument developed was tested for its application to the determination of uranium in solution, in simulated ores, and in naturally occurring ores. This portable X-ray fluorescence instrument is composed of a small radioisotope source for excitation (cobalt-57), a compact proportional counter for detection, a miniaturized electronic package, a recorder for data presentation, and is easily contained in a one-cubic-foot volume. Using this portable instrument, uranium in solution was determined with a relative error of ±2.4%, and in simulated ores with a relative error of ±4.0%. The natural gamma radiation of uranium provides another analytical technique whereby with this instrument uranium in ores was determined with a relative error of ±2.0%.

X-Ray Rayleigh Scattering Method for Determination of Uranium in Solution

X-Ray Rayleigh Scattering Method for Determination of Uranium in Solution

The Determination of Uranium in Solution by X-Ray Spectrometry

A rapid, precise method for the determination of uranium in nitric acid solution is presented. The uranium in solution is excited by a primary x-ray beam from a molybdenum tube. The intensity of the uranium La, emission line is measured by means of a crystal spectrometer employing a scintillation counter and pulse height analyzer. This intensity is converted to concentration by relating to standard solutions The modification of commercial equipment that simplified the solution analysis are described, as are comparisons of various instrument components.

Determination of Uranium in Solution by X-Ray Absorption

Determination of Uranium in Solution by X-Ray Absorption