Determination of natural radioactivity, 222Rn and 220Rn exhalation rates and radiation hazards of fly ash and fly ash brick used in Baotou, China

Abstract

Nat u ral ra dio ac tiv ity lev els, 222 Rn and 220 Rn ex ha la tion rates and ra di a tion haz ards of fly ash and fly ash brick used in Baotou, China were de ter mined. The ac tiv ity con cen tra tions of 226 Ra, 232 Th, and 40 K in fly ash sam ples ranged from 38.81 to 93.73, 40.34 to 135.17, and 66.92 to 290.86 Bq/kg with an av er age of 76.52, 109.95, and 170.72 Bq/kg, re spec tively; while in fly ash brick sam ples, these radionuclides ranged from 42.43 to 71.60, 76.65 to 208.37, and 94.32 to 489.42 Bq/kg with an av er age of 53.83, 101.93, and 266.48 Bq/kg, re spec tively. The ex ha lation rates of 222 Rn and 220 Rn in all de ter mined sam ples were in the range of 1.13-20.50 and 15.60-113.00 mBq/m 2 s, re spec tively. The cal cu lated re sults of the ra dium equiv a lent ac tiv ity, ex ter nal haz ard in dex, in ter nal haz ard in dex, in door an nual ef fec tive dose and out door an nual ef fec tive dose in di cated that fly ashes and fly ash bricks col lected from some brick fac to ries of Baotou would pose ex ces sive ra di a tion risks to in hab it ants and that they are not suit able for use in build ing con struc tion. The nat u ral ra dio ac tiv ity level of fly ash and fly ash brick needs to be con stantly mon i tored con sid er ing the ra di a tion safety of the lo cal res i dents.