Background radiation measurements in the contaminated area with depleted uranium at Al-Nasiriyah station of electricity distribution

摘要

Measurement of background radiation levels, in contaminated area with depleted uranium due to the use of depleted uranium shells through Gulf war in 1991 were carried out in this study. Gamma dose rates were measured using portable survey meter model, Ludlum 2241-2RK -USA. The measured gamma dose rates in study area were found in the range from 17.7 to 81.3 nGy h-1 with mean value 41.9 nGy h-1. The area closed to control room has highest dose rate with mean dose rate 51.6 nGy h-1. The activity concentration of 226Ra, 232Th and 40K were determined using high purity germanium (HPGe) gamma spectrometer. The activity concentration were found in the range from 22.6±0.7 to 44±1 Bq kg-1 for 226Ra, 16.2±0.9 to 32±2 Bq kg-1 for 232Th and 163±2 to 673±8 Bq kg-1 for 40K. The radiological hazard to humans due to the radioactivity arising from radionuclides in soils collected from the studied areas was assessed. The outdoor annual effective dose rate (AEDR) varied from 0.024 to 0.1 mSv, with a mean of 0.053 mSv. The radium equivalent activity (Raeq) varied from 58 ± 2 to 137 ± 10 Bq kg-1 with a mean value of 114 ± 5 Bq kg-1. The values of the external hazard index (Hex) for all soil samples varied from 0.15 to 0.37 with a mean value of 0.30. The results were compared and discuss with the world values recommended by UNSCEAR, 2000.