Determination of ⁹⁰Sr activity concentration in black tea powder used as proficiency test sample by the modified...

Environmental monitoring is very important in nuclear facilities and its surroundings during the construction and operation. It requires many and different radioactivity measurements in order to radiation protection, radioactive waste management and environmental protection. An accurate and reliable determination of Strontium-90 in various environment matrices has been studied with many techniques such as co-precipitation, ion exchange, solvent extraction and extraction chromatography for environmental contamination monitoring purposes. In this study, the method used for dissolution and radiochemical separation to determine strontium-90 activity concentration in tea matrix used as proficiency test sample with liquid scintillation counter was investigated. As a result of these studies, the average mean activity concentration of strontium-90 in proficiency test material was determined as 155 ± 16 Bq kg^-1 dry matter (k = 2) by liquid scintillation efficiency tracing (CIEMAT/NIST) method for seven selected samples. This value was also confirmed by Joint Research Center-Geel with the CIEMAT/NIST method. The proficiency test results for consistency were checked by Dioxon's Q-test. Uncertainties arising from counting statistics, background, weighing, half-life, chemical recovery, efficiency and homogeneity were calculated.