Natural radioactivity and radiological hazard assessment of coal samples collected from Kasimpur thermal power plant, Kasimpur (U.P.), India

Low-level gamma ray spectroscopy with a NaI (TI) gamma radiation detector was used for the measurement of activity concentrations of radionuclides 226Ra, 232Th and 40K. Activity concentrations of radium were found to vary from 12 to 39 Bq kg−1, thorium ranged from 15 to 49 Bq kg−1 whereas 40K ranged from 157 to 460 Bq kg−1. Radium equivalent activity has been found to vary from 50.8 to 118 Bq kg−1 and absorbed gamma dose rates varied from 24 to 53.2 nGy h−1 whereas corresponding outdoor annual effective dose found to vary from 0.029 to 0.065 mSv y−1. The calculated values of Hex and Hin range from 0.13 to 0.31 and 0.16 to 0.41 respectively whereas values of gamma and alpha index vary from 0.19 to 0.42 and 0.06 to 0.19 respectively. The values of hazard index are under the action limit.