Abstract
The technically enhanced concentrations of Naturally Occurring Radioactive Materials (NORMs) were measured in 27 different samples from an oil refinery where crude oil from different wells are processed. The activity concentrations relevant to naturally occurring radionuclides in the samples (waste water, ash and crude oil) were determined by a gamma hyper pure germanium detector. The measured gamma spectrum for each sample were analysed to determine the gamma energy lines emitted from U-238, Th-232 and K-40. The measured NORM concentrations were used to calculate the dose rate for external and internal exposure. The obtained data reveal that in ash samples the Pb-210 shows the highest concentration with an average value of 41.58 Bq/Kg. Furthermore, in waste water Pb-210 shows also a relatively high concentration with an average value of 21.98 Bq/Kg.