Determination Of Mutual Ratios For Specific Activity In Coal, Slag And Fly - Ash Samples From 'Kolubara' Power Plant

Coal as the fossil fuel contains naturally occurring radionuclides and belongs to NORM (Naturally Occurring Radioactive Materials). On the other hand, slag and fly-ash belong to TENORM (Technically Enhanced Naturally Occurring Radioactive Material), and if they are released into the environment an increase and/or redistribution of natural radionuclide content can occur. For the purposes of this study, six sets of samples (18 in total) of TPP Kolubara, slag and fly-ash were collected during the periodical emission tests in May 2012th at steam boilers K3 and K4 of TPP Kolubara, Serbia. Coal, slag and fly-ash samples were prepared for analysis (milled, dried, sieved and weighed) by appropriate standard methods. Prepared samples were placed in 125 mL PVC cylindrical boxes, weighted and sealed with natural wax. Sealed samples were measured with a semiconductor HPGe spectrometer (37 percent relative efficiency) after the radioactive equilibrium was reached. The obtained values of specific activity for coal (Ac), slag (As) and fly - ash (Af) do not differ significantly compared to the values available in the literature. Analysis of determined mutual ratios As/Ac and Af/Ac are consistent, taking into account uncertainties of activity concentrations, with values of approximately 2 and 4, for K3, and 1.5 and 4, for K4. Discrepancies were noted only for 40K (both steam boilers) of As/Ac. Results indicate that further investigation with more samples should be undertaken, and also correlation between radiological and proximate analysis should be determined. (author).