ABSTRACT
The accumulation of scales in the production pipe lines is a common problem in the oil industry, reducing fluid flow and leading to costly remediation and disposal programmes. Thus, an accurate determination of the activity of the radionuclides in scale samples is essential for environmental protection. The present study focuses on the characterization of naturally occurring radioactive materials (NORM) in scales generated from the petroleum industry to develop a suitable NORM waste management plan. The activity concentrations of 226Ra, 228Ra and 210Pb in 32 representative samples, collected from a number of drums at the NORM Decontamination Facility storage, were determined using gamma spectrometry. It was found that the highest concentrations were 2922, 254 and 1794â Bqâ g(-1) for 226Ra, 228Ra and 210Pb, respectively. A comparison to the reported worldwide values was made. Statistical approaches, namely Box plot, ANOVA and principal components analysis were applied on the total results. Maximal correlation was demonstrated by 226Ra activity concentration and count per second (cps) to density ratio. To obtain an accurate characterization of the radionuclides studied in the scale samples, method validation of gamma measurement procedure was carried out, in which minimum detectable activity, repeatability, intermediate precision and assessment of uncertainty were the parameters investigated. The work is a forefront for the proper and safe disposal of such radioactive wastes.
