Natural radioactivity and radon exhalation rates in soil samples collected from near around area of Kota Thermal Power Station, Kota, Rajasthan

The aim of investigation was to measure the amount of gamma-decay, radon exhalation rates and radon effective dose of soil samples collected from near around area of power station. In thermal power station some fly ash is released into the atmosphere and it may collect on the soil around the power plant. Fly ash may change the natural radionuclide concentration in the soil samples. For certain conditions radiation doses from naturally occurring radioactive materials can reach the hazardous radiological levels, so it is necessary to study the radioactivity of materials in our surroundings. In the present study, soil samples were collected from near around area of Kota Thermal Power Station, Kota, Rajasthan. In order to estimate the health risk for the general population, 226Ra, 232Th and 40K as well as the radon exhalation rates were measured. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. 'Can Technique' was adopted for the measurement of Radon exhalation rates, 100 g of samples were taken in the Can and LR-115 type II nuclear track detector was fixed on lid inside the Can. For maintaining the equilibrium Cans were sealed for about 100 days. Radon and its daughter products take about 4 weeks to reach the secular equilibrium. Detector films then chemically etched in 2.5 N NaOH at 60°C for 90 minutes and scanned under the microscope