Partitioning of natural radionuclides in the waste streams of coal-fired utilities

Five coal-fired electric utility plants were sampled to determine radionuclide concentrations in all major process streams. The results, together with plant operating data, were used to track the following six naturally occurring radionuclides: 238U, 226Ra, 210Po, 210Pb, 230Th and 232Th. For each plant, radionuclide balances were computed and the amount and extent of volatilization and enrichment of any radionuclides in the stack effluent were determined. In general, most of the radioactivity was found in boiler bottom ash or particulate control equipment hopper ash; atmospheric emissions were quite small in comparison. Radionuclides in the stack effluent were not detected in the gaseous state and some (especially 210Po and 210Pb) were preferentially associated with the smallest fly-ash particles.