Radon and thoron parallel measurements in Hungary.

Hungarian detectors modified and developed at the National Institute of Radiological Sciences (NIRS), Japan were placed at different sites, including homes and underground workplaces in Hungary, in order to gain information on the average radon (222Rn) and thoron (220Rn) concentration levels. Measurements were carried out in dwellings in a village and a manganese mine in Hungary. The radon and thoron concentrations in the dwellings of the village in the summer period were found to be 154 (17-1083) and 98 (1-714) Bq m(-3), respectively. Considering the results of other radon measurements during the winter (814 Bq m(-3)) and summer (182 Bq m(-3)) periods, the thoron concentrations were also expected to be higher in winter. In the manganese mine, radon and thoron were measured at 20 points for 6 months, changing the detectors each month. The averages were 924 (308-1639) and 221 (61-510) Bq m(-3) for radon and thoron, respectively. These results showed significant variance with the date and place of the measurement.

Population dose in the vicinity of closed Hungarian uranium mine.

In order to determine the exposure to natural sources of radiation for people in the vicinity of remediated Hungarian uranium mine regional surveys were carried out. The surveys evaluated indoor radon concentrations and outdoor and indoor external gamma dose rates. Radon concentration has been measured with nuclear etched track detectors for 4 months in 129 houses in Kovágószolos and in 23 houses in Cserkút. In some houses measurements have been carried out for a year and the measurement results of the 4 months were corrected according to these. The corrected radon concentrations altered between 15 and 2314 Bq m(-3). An average of 257 Bq m(-3) in Kovágószolos and 125 Bq m(-3) in Cserkút was measured. The average was 434 Bq m(-3) for the 48 houses within 100 m of the passage of the former mine that is under the village of Kovágószolos. The higher values of Kovágószolos are likely to be the result of the influence of mining. The terrestrial gamma-ray dose rate was measured outdoors and indoors at these houses. Values of 139 (62-233) nGy h(-1) and 133 (93-275) nGy h(-1) were measured in Kovágószolos and Cserkút, respectively. The average annual effective doses for the two villages studied were 3 and 5 mSv y(-1), but the maximum value was 40 mSv y(-1).

Radiation dose from coal slag used as building material in the Transdanubian region of Hungary.

Coals mined in the Transdanubian region in Hungary have an elevated concentration of (226)Ra, which becomes enriched in the slag after burning. This slag has been used as filling and/or insulating material in building works. The aim of this study was to investigate the radiological situation in this territory in terms of the possible impact of this residual material from coal. Flats in three towns with a coal mine and a coal-fired power plant operating in their neighbourhood were examined. The radionuclide contents (including (226)Ra, (232)Th and (40)K) of the slag used for building were determined, and the slags were categorised according to the international standards and recommendations. The external gamma dose rate and the radon concentration in the sites were measured, and based on these data dose assessments were made. The (226)Ra concentration of the slag was 160-2,893 Bq kg(-1); the indoor gamma dose rates were 82-633 nGy h(-1); the radon concentration measured with a nuclear track detector varied from 29 to 1,310 Bq m(-3); the assessed dose contributions in the three towns were 0.65-1.57 mSv y(-1) due to gamma radiation and 2.2-15.2 mSv y(-1) due to radon.