Radiation Hazard Index in Around NPP Candidate Site in West Kalimantan, Indonesia

Abstract

Before the construction of nuclear power plant (NPP), several documents must be prepared, including environmental and site permit documents. Environmental radiation monitoring is also necessary to ensure public safety and security. The purpose of this research is to obtain data on ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K which will be used for the preparation of site permit documents and environmental documents for NPP in West Kalimantan.
In addition, it also determines the radiation hazard index (considering that there are 3 coal thermal power plants in the vicinity) by calculating the Radium equivalent index (Ra_eq), Representative Level Index (I_γ), Absorbed Dose rate (D), and Annual effective Dose Rate (D_eff) to estimate the potential radiological health risk. Based on this, the measurement of environmental radioactivity around the prospective site of NPP at West Kalimantan was carried out. Measurement of radionuclides using a Gamma Spectrometer an ORTEC P-type coaxial high-purity germanium (HPGe) detector for 24 hours, and for spectrum analysis it was used Personal Computer-based 4096-channel analyzer and processed using Maestro software gamma. The activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K in the soil were 23.18 ± 11.97; 24.03 ± 15.95; 12.18 ± 13.81; 113.80 ± 122.45 and 0.19 ± 0.18 respectively, lower than the world average and levels reported by several other countries (Malaysia, Thailand, China, and Japan). The hazard index values as Radium Equivalent Activity (Ra_eq), Representative Level Index (I_γ), Absorbed Dose Rate (D), and Annual Effective Dose Rate (D_eff) were 68.51 ± 41.43 Bq.kg^-1, 0.49 ± 0.30; 124.14 ± 66.16 nGy.h^-1 and 0.93 ± 0.50 mSv.y^-1 respectively. These values are below the permissible limits and in the safe zone category.