The radiological impact from airborne routine discharges of a modern coal-fired power plant

In this paper the radiological impact from the airborne routine discharges of a modern coal-fired power plant at Langerlo (Belgium) is evaluated. Therefore the natural radioactivity content of the coal and of the fly-ash discharged were measured. With a bi-Gaussian plume model the maximum annual values of the 226Ra concentration in the air (4.5 nBq/m³) and of the total deposition (1.5 mBq/m²) were calculated. The transfers of the radionuclides from air and soil to the biospheric media, exposing man, were modelled and the annual, individual, effective dose to the critical group, after an assumed life span of the power plant of 70 years, evaluated at 0.05 µSv/y. This is several orders of magnitude lower than the annual doses for most power plants reported in the literature. The flue gas purification system, extended with a denitrification unit and a desulphurisation unit, were found to be at the basis for this low impact.