An assessment of absorbed dose and radiation hazard index from soil around repository facility at Bukit Kledang, Perak, Malaysia

The process of natural decay of radionuclides that emit gamma rays can infect humans and other living things. In this study, soil samples were taken at various locations which have been identified around the Long Term Storage Facility (LTSF) in Bukit Kledang, Perak. In addition, the respective dose rates in the sampling sites were measured at 5cm and 1m above the ground using a survey meter with Geiger Muller (GM) detector. Soil samples were taken using a hand Auger and then brought back to the laboratory for sample prepreparation process. The measuring of radioactivity concentration in soil samples were carried out using gamma spectrometer counting system equipped with HPGe detector. The obtained results show, the radioactivity concentration ranged from 11.98 - 29.93 Bq/kg for Radium-226 (Ra-226), 20.97 - 41.45 Bq/kg for Thorium-232 (Th-232) and 5.73 - 59.41 Bq/kg for Potassium-40 (K-40), with mean values of 20.83 +/- 5.88 Bq/kg, 32.87 +/- 5.88 Bq/kg and 21.50 +/- 2.79 Bq/kg, respectively. To assess the radiological hazards of natural radioactivity, radium equivalent activity (R-aeq), the rate of absorption dose (D), the annual effective dose and external hazard index (H-ex) was calculated and compared to the world average values.