Evaluation the annual effective dose of the NORM decontamination workers during cleaning the oil and gas equipment

Abstract

Oil and gas production processing operations have been known to produce a large amount of naturally occurring radioactive materials (NORMs) at elevated concentrations as by-product waste streams. This means that TE-NORM (technologically-enhanced naturally occurring radioactive materials) wastes from the oil \& gas industry may generate radiation exposure levels, which require attention and continuous monitoring during NORM decontamination of oil and gas equipment. This exposure is mostly caused by external and internal radiation coming from the Ra-226 \& Ra-228 (U-238 and Th -232 series) radionuclides and their progenies. This study focuses on follow up of the annual effective dose for workers during decontaminating naturally occurring radioactive materials (NORM) of oil and gas equipment. The external effective dose was evaluated using thermoluminescence detector (TLD). The obtained data showed that the range of the annual dose was from 1.07 to 1.78 mSv and the average dose of the ten workers under investigation was 1.4 +/- 0.24 mSv. The average dose is about 7 \% of the occupational annual dose limit. It is concluded that protective measures against external and internal contamination helped in the protection of the workers against NORM hazards).