Radionuclide content of NORM by-products originating from the coal-fired power plant in Oroszlány (Hungary)

Abstract

At the Thermal Power Plant in Oroszlány (Hungary), a huge amount of by-products have been produced since 1961. In this survey, coal and other by-products were examined (fly ash, bottom ash, fluidised bed bottom ash, gypsum and slurry-type ash). The natural isotopes were determined using an HPGe detector. It was found that the radionuclide content of coal was significantly lower (226Ra = 45.3±6.3, 232Th = 26.3±5.7 and 40K = 210±21 Bq kg-1) than that in the case of ashes other than the fluidised type. The average values of the bottom ash-deposited in the largest quantities-were three times higher than those for coal (226Ra = 144±18, 232Th = 84.3±14 and 40K = 260±25 Bq kg-1). In the case of fractionised bottom ash, the radionuclide content of < 0.1 mm was 45 % higher than that of > 1.6 mm and the massic radon exhalation of < 0.1 mm was approximately four times higher than that above this range.