Measurement of natural radioactivity, radon exhalation rate and radiation hazard assessment in Indian cement samples

Building materials are assumed to be the second source of Radon inside buildings. Due to low level of radon emanation from these materials, long term measurements are needed. Radiation doses from the building materials vary depending upon the natural radionuclides Ra-226, Th-232 and their daughter products and K-40 present in them. Cement is the main and important component used in the construction of buildings in many countries. These radio nuclides pose exposure risk due to their gamma ray emission and internally due to radon and its progeny that emit alpha particles. In the present study radon exhalation rate and the activity concentration of Ra-226, Th-232 and K-40 radionuclides in cement samples used in Aligarh region (U.P.), 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. From the measurements activity concentration of radionuclides Ra-226, Th-232 and K-40 vary from 9 to 28 Bq kg(-1), 21 to 43 Bq kg(-1) and 280 to 554 Bq kg(-1) with overall average value of 19 Bq kg(-1),35 Bq kg(-1) and 406.7 Bq kg (-1) respectively. Radon equivalent activity (Ra-eq) and external hazard index (H-ex) have been found to vary from 60.8 to 121 Bq kg(-1) and 0.16 to 0.30 respectively. The values are lower than the recommended safe values. (C) 2015 The Authors. Published by Elsevier B.V.