Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review

Abstract Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of 40 K and of 238 U, 232 Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y −1 ), the major part of which (99 %) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg −1 for 238 U, from 44 to 255 Bq kg −1 for 226 Ra, from 59 to 205 Bq kg −1 for 210 Pb, from 9 to 41 Bq kg −1 for 228 Ra ( 232 Th) and from 59 to 227 Bq kg −1 for 40 K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3–1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg −1 for 238 U, from 142 to 605 Bq kg −1 for 226 Ra, from 133 to 428 Bq kg −1 for 210 Pb, from 27 to 68 Bq kg −1 for 228 Ra ( 232 Th) and from 204 to 382 Bq kg −1 for 40 K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5 man-Sv (GW a) −1 for typical old and modern coal-fired power plants, respectively.