Assessment of radiogenic heat production due to 238U, 232Th and 40K in surface soils of Ortum region, west Pokot county, Kenya

Mukanda Kere Wanyama¹, Michael Nakitare Waswa², and Felix Omonya Wanjala³

¹ Department of Science, Technology & Engineering; Kibabii University, 1699-50200 Bungoma

²Department of Science, Technology & Engineering; Kibabii University, 1699-50200 Bungoma

³IAEA, Vienna, Austria

Abstract

The activity concentrations of ²³⁸U, ²³²Th and ₄₀K in Bq/kg were determined using a HPGe detector at the Institute of Nuclear Science and Technology at the University of Nairobi (Kenya). The activity concentrations were then converted into ppm (²³⁸U and ²³²Th) and % for ⁴⁰K that were used for computing Radiogenic Heat Production (RHP) for individual radionuclides and the overall RHP contributed by the three radionuclides. The average activity concentrations were 3.198753ppm, 13.42265ppm and 1.372154% for ²³⁸U, ²³²Th and ⁴⁰K respectively. The average RHP for the individual radionuclides was found to be 0.239883µW/m³, 0.2658µW/m³ and 0.036378µW/m³ for ²³⁸U, ²³²Th and ⁴⁰K respectively. the overall RHP contribution by the three radionuclides was found as 0.540764 µW/m³. All the RHP values for the individual radionuclides including their overall contribution was below the world RHP value of 1µW/m³. The findings of this study will provide benchmark information on RHP status of the study area that can be extended to other areas to enable possible geothermal energy exploitation.

Keywords

radiogenic heat production; natural radioactivity; elemental concentration.

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