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1Masego E Mothapo, 1Fhulufhelo Nemangwele, 2Le Roux Rikus ,3Jacques Bezuidenhout
1Faculty of Science, Engineering and Agriculture, Department of Physics, University of Venda, Thohoyandou, 0950
2Faculty of Military Science, Department of Military Technology, Stellenbosch University, Saldanha, 7395
3Faculty of Military Science, Department of Physics, Stellenbosch University, Saldanha, 7395
Radiometric measurements were conducted at the West Coast Fossil Park, known for elevated levels of natural radionuclides - primarily uranium, thorium and potassium - associated with phosphate-rich sediments. The presence of elevated radionuclides in phosphatic rocks poses potential environmental and health risks, resulting in the need for radiological assessment. A UAV-based system with a 3x3 NaI(Tl) scintillation detector was used to survey and map the site, and the activity concentrations determined using full-spectrum analysis. The analysis revealed peaks corresponding to the decay series of 238U, 232Th, and 40K: at energies of 186, 295, 352, 609, and 1765 keV (U-238), 238, 338, 583, and 911 keV (Th-232), and 1460 keV (K-40). These energies confirmed elevated levels of all three principal naturally occurring radionuclides at the site. The results indicated high concentrations of uranium [RL1.1]up to 1851 Bq/kg, thorium up to 147 Bq/kg, and potassium up to 1851 Bq/kg, associated with the geology and past mining activities at the site, demonstrating the suitability of full-spectrum analysis for NORM assessment at legacy phosphate mining sites.
Keywords: UAV-based system, Phosphate rock, Full-spectrum analysis, NORM, West Coast Fossil Park
| Apply for student award at which level: | MSc |
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