Techniques for chemical analysis of radionuclides in fly ash: an evaluation. Final report

The objectives of this project are to: (a) describe and evaluate the analytical techniques for radionuclide measurements of coal and fly ash utilized during previous studies, (b) recommend a comprehensive set of procedures for future investigations, and (c) place in perspective the radionuclide emissions from coal combustion. Numerous measurement techniques, ranging from semi-quantitative to quantitative and from general to radionuclide-specific, have been applied during previous studies. These analytical measurement techniques are described and evaluated. The evaluation criteria included radionuclide specificity, potential for interferences, sensitivity, precision and accuracy. After evaluation of the various analytical alternatives, a recommended set of procedures for radionuclide quantification in coal and fly ash media is presented. The recommended procedures utilize a combination of gamma and x-ray spectrometry, along with radiochemical separations and alpha energy analysis to yield a complete radionuclide characterization with a typical analytical precision for an individual radionuclide on the order of +- 5 to 10%. The radionuclide concentrations in emitted ash, coal, and fly ash are placed in prespective by comparison with the concentrations occurring in natural crustal materials