Kajian Risiko Pajanan Sinar Gama dan Radon pada Pekerja di Area Terowongan Eksplorasi Uranium Remaja, Kalimantan Barat

ABSTRAK Kajian risiko pajanan radiasi gama dan gas radon dilakukan di area terowongan eksplorasi uranium dalam upaya melindungi pekerja dari bahaya radiasi pengion di tempat kerja. Pengukuran pajanan sinar gama dan konsentrasi gas radon dilakukan di dalam terowongan eksplorasi uranium Remaja dan sekitar kamp pekerja di daerah Kalan, Kalimantan Barat. Pajanan sinar gama diukur menggunakan surveimeter gama, sementara pajanan radon (222Rn/220Rn) menggunakan detektor pasif RADUET. Konsentrasi gas radon dan toron di dalam terowongan secara umum cukup tinggi, berkisar antara 188,84 hingga 495,86 Bq/m 3 (rata-rata 375,80 Bq/m 3 ) sementara toron berkisar antara 58,07 hingga 340,73 Bq/m 3 (rata-rata 189,80 Bq/m 3 ). Nilai tersebut berada di atas reference level radon (300 Bq/m 3 ) yang disaranakan oleh International Commission on Radiation Protection (ICRP). Dosis efektif tahunan sinar gama mencapai nilai 147,88 mSv di dalam terowongan eksplorasi. Nilai tersebut berada di atas nilai batas dosis untuk pekerja, yaitu 20 mSv. Pengendalian pajanan sangat penting dilakukan dengan memenuhi prinsip “ as low as reasonably achievable” (ALARA) dan proteksi radiasi eksterna untuk melindungi pekerja di dalam terowongan dari masalah kesehatan yang disebabkan oleh pajanan dari sinar gama, radon, dan toron. ABSTRACT A risk assessment of gamma radiation and radon gas exposure is carried out in the uranium exploration tunnel area to protect workers from the ionizing radiation hazards in the workplace. Measurement of gamma-ray exposure and radon gas concentrations were carried out in Remaja uranium exploration tunnel and around the workers camp in Kalan Area, West Kalimantan. Gamma exposure was measured using a gamma survey meter while radon (222Rn/220Rn) using RADUET passive detector. The concentrations of radon and thoron gas inside the tunnel generally are high, ranging from 188.84 to 495.86 Bq/m 3 (375.80 Bq/m 3 average) and 58.07 to 340.73 Bq/m 3 (189.80 Bq/m 3 average) respectively. These values are above the radon reference level (300 Bq/m 3 )which is recommended by the International Commission on Radiation Protection (ICRP). The annual gamma effective dose reaches 147.88mSv inside the tunnel. This value is exceeding the 20 mSv dose limit value for workers. It is necessary to control the exposure by fulfilled the principle of “ as low as reasonably achievable” (ALARA) and external radiation protection to secure workers inside the tunnel from a health issue caused by gamma-ray, radon, and thoron exposures.