Natural radioactivity of coal and itsby-products in the Baoji coal-firedpower plant, China

摘要

Coal, bottom ash and fly ash from the Baoji coal-firedpower plant, China were measured for ~(226)Ra, ~(232)Th and~(40)K by a Nal(Tl) gamma-ray spectrometer. The results showthat fly ash or bottom ash contain three to six timesmore natural radionuclides than feed coal. The resultsare compared with the available data from other coun-tries. Radium equivalent activity and external indexare calculated for by-products to assess the radiationhazards arising due to the use of these ash samples inthe construction of dwellings. Some fly-ash sampleshave radium equivalent activities and external hazardindex values more than 370 Bq kg~(-1) and unity respec-tively. The absorbed dose rate at 1 m above the ashpond was (155 nGy IT~(-1) higher than the global averagevalue of 55 nGy IT~(-1) and the Chinese average value of81.5 nGy IT~(-1). The corresponding annual external effe-ctive dose is estimated to be 0.191 mSv y~(-1), which is lessthan that (0.46 mSv y~(-1)) in areas of natural backgroundradiation.