An investigation of radon exhalation rate and estimation of radiation doses in coal and fly ash samples

Coal is a technologically important material used for power generation. Its cinder (fly ash) is used in the manufacturing of bricks, sheets, cement, land filling etc. Coal and its by-products often contain significant amounts of radionuclides, including uranium which is the ultimate source of the radioactive gas radon. Burning of coal and the subsequent atmospheric emission cause the redistribution of toxic radioactive trace elements in the environment. In the present study, radon exhalation rates in coal and fly ash samples from the thermal power plants at Kolaghat (W.B.) and Kasimpur (U.P.) have been measured using sealed Can technique having LR-115 type II detectors. The activity concentrations of 238U, 232Th, and 40K in the samples of Kolaghat power station are also measured. It is observed that the radon exhalation rate from fly ash samples from Kolaghat is higher than from coal samples and activity concentration of radionuclides in fly ash is enhanced after the combustion of coal. Fly ash samples from Kasimpur show no appreciable change in radon exhalation. Radiation doses from the fly ash samples have been estimated from radon exhalation rate and radionuclide concentrations.