ABSTRACT
Objective To experimentally verify the precision and accuracy of determining tritiated water in ambient air using the desiccant adsorption sampling–high temperature negative pressure desorption of liquid water (containing HTO)–liquid Scintillation counter method, and to provide technical support for developing standard methods for monitoring tritiated water in ambient air. Methods The relative standard deviation and recovery of multi-group samples were verified by collecting, testing, and analyzing environmental samples with different activity concentrations. The uncertainty of the method was evaluated, the main uncertainty components were identified, and the reliability of measurement results was analyzed. Through experimental comparison of different methods, the differences in the test results of different methods were examined. Results The relative standard deviation of multiple samples ranged from 6.7% to 7.9%, the recovery ranged from 95.7% to 97.3%, and the uncertainty was greatly affected by the sample counting rate, with no significant difference as compared to condensation sampling method. Conclusion The precision and accuracy of this method meet the requirements of environmental authorities for monitoring tritiated water in ambient air, and it can be widely used in the monitoring of tritiated water in ambient air.
ABSTRACT
Objective To explore the method for measurement of tritium in nuclear power plant liquid effluent purified by a mixed ion-exchange resin, to verify the feasibility of the method by experiments, and to provide technical support for the development of standard methods for the measurement of tritium in liquid effluent of nuclear power plants. Methods The purification effect of the mixed ion-exchange resin was determined by measuring the quenching factor, conductivity, and β-nuclide adsorption efficiency of the samples purified using the resin. A comparison was made between the ion-exchange resin method and the atmospheric distillation method for tritium determination. The precision and accuracy of the method were verified by calculating the relative standard deviation and the recovery in repeated measurement of samples with different activity concentrations and spiked samples. Results There were no significant differences in quenching factor, conductivity, and tritium activity concentration between the two methods. The adsorption efficiencies of EC20MB resin for common β-nuclides such as carbon, iron, nickel, strontium, yttrium, and cesium ranged from 99.28% to 99.88%. Repeated measurement of the same sample showed relative standard deviations of 5.2%-9.4% and recoveries of 86.8%-107%. Conclusion There were no significant differences between the results of the ion-exchange resin purification method and the atmospheric distillation method. The precision and accuracy of the method met the requirements of the ecological and environmental management authorities for monitoring tritium in liquid effluent from nuclear power plants. This method can be widely used in daily monitoring work.
ABSTRACT
Objective To optimize the measurement and analysis method for carbon-14 in environmental biological samples, and to provide technical support for the formulation of standard methods for carbon-14 measurement in environmental biological samples. Methods Through the optimization research on the carbon dioxide absorption method, the moisture content and carbon content of biological samples were measured with the moisture meter and the element analyzer according to the simplified personnel operation and the optimized process steps of the method, and intra- and inter-laboratory validation of the method was carried out. Results Under typical conditions, the lower limit of detection of the method reached 3 Bq/kg, and there were a relative standard deviation within laboratories of less than 17% and a relative standard deviation between laboratories of less than 14%, with a relative error of less than 19%. Most of the sample pretreatment was directly completed by the instrument and equipment, which improved the precision and accuracy of the measurement of moisture content and carbon content in samples, and reduced the influence of experiment personnel’s operation differences on the test results. Conclusion The lower limit of detection, precision, and accuracy of the optimized method meet the relevant requirements for the determination of carbon-14 in biological samples.