Innovative procedure for the determination of gross-alpha/gross-beta activities in drinking water

Simultaneous determination of gross alpha/beta activities in water by liquid scintillation counting and its applications in the environmental monitoring

Based on the standards of ISO11704-2018 and ASTM D7283-17, a method for simultaneous determination of gross alpha and gross beta activity concentrations in water by liquid scintillation counting (LSC) was established, which can be applied to various types of water samples in routine monitoring, such as drinking water, groundwater, geothermal water, seawater, and radioactive wastewater. The sample's pH value and concentrated volume must be controlled to avoid quenching as much as possible. The validation tests show that the deviations of gross alpha and gross beta activities can satisfy quality control requirements in a wide range of activity ratios from 1:102 to 67:1. For the actual samples, the measurement results of the LSC method are in good agreement with those of the thick source method, in which the relative deviations of gross alpha and gross beta are both less than 15% for these two methods. Moreover, the LSC method performs better in detection limit and has a simpler pretreatment process than the thick source method.

Development of a rapid method for extraction of uranium from uranium bearing materials using ionic liquid as extracting agent from basic media

The paper presents the development of a rapid method for the direct determination of uranium using liquid scintillation analysis in uranium bearing materials with different uranium concentrations and with different impurity levels (U-ore, Uranium ore concentrate (UOC) and U-metal). Uranium extraction was carried out using hydrophobic ionic liquid Aliquat-336 thiosalicylate, ([A-336][TS]) from diluted samples in basic medium followed by liquid scintillation counting (LSC). Extraction efficiencies for uranium from aqueous medium was studied with very small volumes of ionic liquid under varying volume, pH and uranium concentration of the aqueous medium. Maximum extraction efficiency was achieved near pH 8-11. Uranium was successfully re-extracted from organic medium with nitric acid and electroplated onto stainless steel planchette for alpha spectrometry determination. Maximum re-extraction efficiency with 1 M HNO₃ combined with electroplating efficiency observed was 80%. The methodology was applied for real samples. The uranium extraction efficiency using ionic liquid was about 85% for U-metal and UOC samples with comparatively low impurity level; whereas extraction efficiency for U-ore samples was found to be less than 40%. The technique can be applied for nuclear forensic applications as well as nuclear emergency scenarios for a quick initial assessment and isotopic analysis of uranium in the samples.

Simple Radiometric Determination of Strontium-90 in Seawater Using Measurement of Yttrium-90 Decay Time Following Iron-Barium Co-precipitation

A radiometric quantitative methodology of ⁹⁰Sr in seawater was developed using a measurement of the ⁹⁰Y decay time following iron-barium co-precipitation. With calculations of its decay time, the radioactivity of ⁹⁰Sr can be indirectly determined under conditional environmental samples. In addition, to avoid the interference of other radionuclide, the prepared samples were measured using a germanium semi-conductivity detector; then, the deposited radioactivity was subtracted from the actual measurement values of beta-ray counting. In this paper, the seawater samples were collected within 2 km around Fukushima Daiichi Nuclear Power Plants during the term from October 2011 to March 2012. This method showed good linearity between the ⁹⁰Sr concentration and the total beta counting following the proposed method, with a correlation coefficient of 0.99 in seawater sample analysis. No interference that was caused by other radionuclides, such as radioactive cesium, was not observed in the quantification of ⁹⁰Sr. The whole process requires 12 h to quantify ⁹⁰Sr; this time is 1/40 shorter than traditional milking-low background gas-flow counting method. The lower limit of detection (average value n = 60) of the ⁹⁰Sr radioactivity was shown to be 0.03 Bq/L (uncertainty 4.2%).

Multivariate statistical analyses of artificial radionuclides and heavy metals contaminations in deep mud of Keban Dam Lake, Turkey

On the basis of the artificial radioactive and heavy metal compositions, factor and cluster analyses are employed to identify the inter-relationship among different variables and their similarity groups. In this paper, 15 physico-chemical variables, including the activities of 137Cs, 90Sr, total alpha, total beta, and concentrations of Fe, Mg, Ca, K, Na, Zn, Cu, Cr, Co, Ni, and Mn, are used for the application of the proposed methodologies. The spatio-temporal samples of these variables are collected from deep mud at about 30-35 m mean depth in the reservoir of Keban Dam Lake, which is located in the eastern part of Turkey. Spatially, there are 20 sampling sites at the dam with 150 km2 lake surface area where samples were taken in 2006. The lake is affected by man-made and industrial influxes. The application of the factor and cluster analysis methods yields that the former method reduces the number of variables into six factors with 77.2% variance explanation whereas the latter yields three distinctive groups of the same variables.