Radioactivity Concentrations Of 238U Research Articles

Natural and artificial radionuclides in tea samples determined with gamma spectrometry

The aim of the present work is to determine natural and artificial radioactivities in the twenty tea samples available at the local Vietnamese market using gamma spectrometry with HPGe detector. The radioactivity concentrations of 238U, 232Th, 40K and 137Cs in their mean value were 3.4 ± 0.3 (Bq kg−1), 16.4 ± 0.8 (Bq kg−1), 564 ± 8 (Bq kg−1), and 1.6 ± 0.1 (Bq kg−1), respectively. The result was compared with the those found in the previous research.

Assessment of Radioactivity in Concrete Made with e-Waste Plastic

Abstract The paper reports the impact of e-waste plastic [high-impact polystyrene (HIPS)] mixing in concrete on its radioactivity profile. The concrete was prepared with HIPS as a partial replacement for coarse aggregate in varying percentages by volume and radioactivity concentrations of 238U, 232Th, and 40K were measured using gamma-ray spectrometer and radon activity by solid state nuclear track detector (SSNTD) technique. Both gamma radiation and radon activity in standard concrete and concrete with HIPS were well within the permissible limit. However, the gamma-radiation level and radon activity decreased with an increase in HIPS content of the concrete. The study concludes that the concrete with HIPS does not pose any radiation hazard and, hence, is suitable as a construction material.

Chemical distribution of hazardous natural radionuclides during monazite mineral processing

It is very important to calculate the radioactivity concentration for low-grade monazite ore (50%) and different other materials produced as results of chemical processing stages to avoid the risk to workers. Chemical processing of low-grade monazite pass through different stages, washing by hydrochloric acid and digested with sulfuric acid and influence of pH on the precipitation of rare earth elements has been studied. The radioactivity concentrations of 238U(226Ra) and 232Th as well as 40K were calculated in crude low-grade ore and found to be 54,435 ± 3138, 442,105 ± 29,200 and 5841 ± 345 Bq/kg, respectively. These values are greatly higher than the exempt levels 25 Bq/kg. After chemical digestion of the ore, the results demonstrated that un-reacted material contains significant radioactivity reached to approximately 8, 13 and 23% for 238U, 232Th and 40K, respectively. The results show that 60% of 232Th are located in the digested white slurry with small portions of 238U and 40K. Most of 238U radioactivity is extracted in the green phosphoric acid which produced from conversion of P2O5 by H2SO4 into phosphoric acid. The average values of the Raeq for monazite ore, un-reacted black precipitate, white precipitate, brown precipitate and crystalline material samples were calculated and found to be 687,095 ± 44,921, 85,068 ± 5339, 388,381 ± 22,088, 313,046 ± 17,923 and 4531 ± 338 Bq/kg, respectively. The calculated values of Raeq are higher than the average world value (it must be less than 370 Bq/kg). Finally the external hazardous, internal hazardous and Iγr must be less than unity. This means that specific radiation protection program must be applied and implemented during monazite processing.

Concentration measurements of uranium, thorium and their daughter products in water produced from and near oil fields in north of Iraq using SSNTRD’s passive method

The radioactivity concentrations of 238U, 232Th and their daughter products in water samples collected from different oil fields and sources in north of Iraq, were determined by using CR-39 and LR-115 SSNTRDs. It was found that the concentrations of 238U and 232Th vary between 0.20 and 3.50 ppm and from 0.03 to 1.83 ppm, respectively. According to the recommended values and the calculated annual effective dose, most of the produced water from the studied oil fields is not useful for any direct purpose.

Distribution of 238U, 226Ra, 232Th and 40K in soil samples around Tarapur, India

The radioactivity concentrations of 238U, 226Ra, 232Th and 40K in soil samples around Tarapur vary from 11.5 ± 2.6 to 50.3 ± 6.6, 14.9 ± 0.6 to 40.5 ± 1.2, 18.1 ± 0.4 to 75.0 ± 1.5 and 130.1 ± 1.6 to 295.1 ± 2.6 Bq/Kg respectively. The measured activity concentrations for 238U and 226Ra were compared and found in good agreement with the Indian as well as world average. The average 232Th and 40K concentrations in Tarapur were lower than the Indian average value.

BACKGROUND RADIATION MEASUREMENTS AND CANCER RISK ESTIMATES FOR SEBINKARAHISAR, TURKEY.

This paper presents the measurement results of environmental radioactivity levels for Şebinkarahisar district (uranium-thorium area), Giresun, Turkey. The radioactivity concentrations of 238U, 232Th, 40K and the fission product 137Cs in soil samples collected from 73 regions from the surroundings of the study area were determined. In situ measurements of the gamma dose rate in air were performed in the same 73 locations where the soil samples were collected using a portable NaI detector. Also the mean radioactivity concentrations of 238U, 232Th and 40K in rock samples collected from 50 regions were determined. The mean estimated cancer risk value was found. The seasonal variations of the indoor radon activity concentrations were determined in the 30 dwellings in the study area. In addition, the mean gross alpha, gross beta and radon activities in tap water samples were determined in the same 30 dwellings. The excess lifetime cancer risk was calculated using the risk factors of International Commission on Radiological Protection and Biological Effects of Ionizing Radiation. Radiological maps of the Şebinkarahisar region were composed using the results obtained from this study.

Natural radioactivity in soil samples of Yelagiri Hills, Tamil Nadu, India and the associated radiation hazards

The natural radioactivity of soils at Yelagiri hills has been studied in this paper. The radioactivities of 25 samples have been measured with a NaI(Tl) detector. The radioactivity concentrations of 238U, 232Th and 40K ranged from ≤2.17 to 53.23, 13.54 to 89.89 and from 625.09 to 2207.3Bqkg−1, respectively. The measured activity concentrations for these radionuclides were compared with world average activity of soil. The average activity concentration of 232Th in the present study is 1.19 times higher than world median value while the activity of 238U and 40K is found to be lower. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity Raeq, the absorbed dose rate DR, the annual effective dose rate and the external hazard index (Hex) have been calculated and compared with the internationally approved values. The study provides background radioactivity concentrations in Yelagiri hills.

A device for uranium series leaching from glass fiber in HEPA filter

For the disposal of a high efficiency particulate air (HEPA) glass filter into the environment, the glass fiber should be leached to lower its radioactive concentration to the clearance level. To derive an optimum method for the removal of uranium series from a HEPA glass fiber, five methods were applied in this study. That is, chemical leaching by a 4.0 M HNO3–0.1 M Ce(IV) solution, chemical leaching by a 5 wt% NaOH solution, chemical leaching by a 0.5 M H2O2–1.0 M Na2CO3 solution, chemical consecutive chemical leaching by a 4.0 M HNO3 solution, and repeated chemical leaching by a 4.0 M HNO3 solution were used to remove the uranium series. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 5 h by the 4.0 M HNO3–0.1 M Ce(IV) solution were 2.1, 0.3, 1.1, and 1.2 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 36 h by 4.0 M HNO3–0.1 M Ce(IV) solution were 76.9, 3.4, 63.7, and 71.9 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 8 h by a 0.5 M H2O2–1.0 M Na2CO3 solution were 8.9, 0.0, 1.91, and 6.4 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after consecutive leaching for 8 h by the 4.0 M HNO3 solution were 2.08, 0.12, 1.55, and 2.0 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after three repetitions of leaching for 3 h by the 4.0 M HNO3 solution were 0.02, 0.02, 0.29, and 0.26 Bq/g. Meanwhile, the removal efficiencies of 238U, 235U, 226Ra, and 234Th from the waste solution after its precipitation–filtration treatment with NaOH and alum for reuse of the 4.0 M HNO3 waste solution were 100, 100, 93.3, and 100%.

Exposure rates and radiation doses due to ambient gamma rays/Anbar governorate.

Radiation exposure rates and radiation doses were measured in 174 locations in the Western Desert. Exposure rates were measured 1m above the ground with NaI (Tl) scintillation detector. Total radiation doses due to external exposure to the ambient gamma ray in the same previous locations were measured with FAG-FH 40 F2. The radioactivity concentrations of 238U, 232Th and 40K in selected soil and rocks samples were measured using gamma spectroscopy system based on high purity Germanium detector. Then, absorbed doses due to presence of 238U, 232Th and 40K in the samples were estimated. The exposure rates ranged between (5.0-71.7) ىR/h, while the average of radiation dose due to the exposure to ambient gamma ray ranged between (0.7-3.32) mSv/y. Doses due to expose to the concentrations of 238U, 232Th and 40K in the soil and rocks of the Western Desert were calculated. The average of these exposure doses ranged between (0.03-1.84)mSv/y.

Radioactivity Concentrations in Soils in the Qingdao Area, China

The specific activity concentrations of radionuclides (238)U, (232)Th, and (40)K of 2300 sampling points in the Qingdao area were measured by an FD-3022 gamma-ray spectrometer. The radioactivity concentrations of (238)U, (232)Th, and (40)K ranged from 3.3 to 185.3, from 6.9 to 157.2, and from 115.8 to 7834.4 Bq kg(-1), respectively. The air-absorbed dose at 1 meter above ground, effective annual dose, external hazard index, and radium equivalent activity were also calculated to systematically evaluate the radiological hazards of the natural radioactivity in Qingdao. The air-absorbed dose, effective annual dose, external hazard index, and radium equivalent activity in the study area were 98.6 nGy h(-1), 0.12 mSv, 0.56, 197 Bq kg(-1), respectively. Compared with the worldwide value, the air-absorbed dose is slightly high, but the other factors are all lower than the recommended value. The natural external exposure will not pose significant radiological threat to the population. In conclusion, the Qingdao area is safe with regard to the radiological level and suitable for living.

Radioactivity concentrations in soils of the Xiazhuang granite area, China

The natural radioactivity of soils at the Xiazhuang granite massif of Southern China has been studied. The radioactivities of 55 samples have been measured with a low-background HPGe detector. The radioactivity concentrations of 238U and 40K ranged from 40.2 to 442 and from 442 to 913 Bq/kg, respectively, while the radioactivity concentration of 232Th varied only slightly. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity ( R a eq ) , the absorbed dose rate ( D ˙ ) , the annual effective dose rate and the external hazard index ( H ex ) have been calculated and compared with the internationally approved values. The study provides background radioactivity concentrations in a granite area, specifically, the area in the vicinity of a uranium mine in Southern China. The data can be used in exploring granite-type uranium deposits.