Dose contribution from buildings containing bottom ash insulation with elevated concentrations of natural radionuclides

Application of coal combustion ashes in building materials has been limited by the presence of minor components such as radioactive substances. During the combustion of coal, the gamma radiation of the enriched 226Ra, 232Th and its daughter elements, 40K and the possibly exhaled radon may result in heavy radiation load in the ash. In Sopron, in the case of the 97 apartments examined, the estimated effective gamma dose was 1.05 (0.63–2.14)mSvy-1 in apartments with ash from the power station, while it was 0.55 (0.34–0.88)mSvy-1 in apartments without ash. In 54 of the examined apartments, the committed effective dose stemming from radon was 7.3 (3.0–13.6)mSvy-1 in buildings with ash from the power station, while it was 2.8 (1.3–6.6)mSvy-1 in buildings without ash.