Possibilities of intervention to reduce doses in buildings due to natural radionuclides

The use of coal slags with elevated Ra-226 concentration as building materi al may affect indoor dose, which originates from external radiation and the inhalation of radon's decay products. From the radiological point of view it may be significant, so we have investigated the possibilities of the int ervention. It has been found based on the modeling, that the dose rate coul d be decreased by 70-80% using appropriate (8-10 cm) thick concrete or bari te concrete layers. The frequent airing resulted in a significant decrease in the radon concentration, although this method is less economical conside ring the heating expenses. The ventilation method resulted in a 70% decrease (the efficiency probably increases with higher ventilator power).