Radon, thoron and their progeny levels in some industrial units

The increase in radioactivity of soil, water and atmosphere around industrial plants is caused by combustion of coal in them. As the radon in the atmosphere, soil, ground water, oil and gas deposits contributes the largest fraction of the natural radiation dose to populations, therefore, tracking its concentration is thus fundamental for radiation protection, health and hygiene point of view. In the present study, measurements of radon, thoron and their progeny concentration in the environment of some coal fired thermal power plants and paper mill of north India have been made using Solid State Nuclear Track Detectors (SSNTD). The radon thoron twin dosimeter cups are being used for the study. Three pieces of LR-115 Solid State Nuclear Track Detectors are fixed in the dosimeters and are suspended in the units for three months. One gives radon, thoron and progeny concentration, second gives radon and thoron concentration while the third gives only the radon concentration. The annual effective doses received by the workers in these plants have also been calculated. The fly ash and coal dust produced by grinding and burning of coal in thermal power plants may cause an increase in radon concentration in and around thermal power plants. To observe this effect the radon exhalation rates from soil samples collected from in and around the thermal plants have also been calculated. The results indicate some higher radon levels in coal and fly ash handling areas of these plants compared with other locations. (author)