Measurement of radon exhalation rate and radiation doses in fly ash samples

Coal based thermal power plants contribute about similar to 72% of the power generation in India. Indian coal is of bituminous type, having a high ash content with 55-60% ash. Due to considerable environmental importance the collected fly ash has become a subject of worldwide interest in recent years. In the present study radon exhalation rate and the activity concentration of Ra-226, Th-232 and K-40 radionuclides in fly ash samples from Kasimpur Thermal Power Plant, Aligarh, Uttar Pradesh, India have been measured by 'Sealed Can technique' using LR-115 type II detectors and a low-level NaI (Tl)- based gamma-ray spectrometer, respectively. Radon exhalation rate has been found to vary from 57.1 +/- 5.3 to 119.4 +/- 7.7 mBq m(-2) h(-1) with an average value of 87.3 +/- 5.8 mBq m(-2) h(-1). Activity concentration of Ra-226 ranged from 20.0 +/- 8.5 to 30.0 +/- 9.7 Bq kg(-1) with an average value 23.4 +/- 9.0 Bq kg(-1), Th-232 ranged from 17.0 +/- 9.9 to 69.0 +/- 13.8 Bq kg(-1) with an average value of 46.5 +/- 12.1 Bq kg(-1) and K-40 ranged from 130.0 +/- 7.2 to 332.0 +/- 11.1 Bq kg(-1) with an average value of 177.0 +/- 8.1 Bq kg(-1).