Average World Value Research Articles

Radiological Mapping of Al-Dabaa Site at Low Depth Profile for Evaluation its Suitability for Disposal of Radioactive Wastes

Disposal sites use series of natural and engineered barriers to contain either radioactive wastes and or spent nuclear fuel. Migration of radionuclide and their pathways studies are carried out as selection criteria of radioactive waste disposal/storage facility. In the framework of the planned NPPs program at Al-Dabaa site, radiological mapping at low depth profile of a specific area within the site has been carried out for evaluation its suitability for disposal of radioactive wastes. Twenty samples were collected from different bore holes of about 12-meterdepthprofile.The samples were transported to the laboratory and prepared for non-destructive assay using well calibrated 60% efficiency High-Purity Germanium (HpGe) detector. The natural radioactivity of 235U, 238U (234Th), 226Ra, 232Th and 40K were determined and quantified. The 235U/238U activity ratios were also calculated and found to be within the natural signature. The Absorbed dose rates (nGy/h) were also calculated and found in the average world value; 59nGy/h. The man-made 137Cs was also found in ultra-low activity concentrations, where the highest value was found to be 0.00987 Bq/kg. The mineralogy of the collected site samples was also investigated by x-ray diffraction (XRD) analysis technique to identify and determine the major mineral structure of the samples. It was observed that Dolomite and Calcite are the major minerals of the investigated site. The results are discussed and represented as histograms, contour mapping and 3D correlations. These results are also going to be used as inputs and bases for a future work; code modeling for evaluation of Al-Dabaa site.

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.

Химическая денудация на горной территории Азербайджана

Chemical denudation (dissolved matter runoff) in mountain rivers in comparison with mechanical denudation (sediments runoff) has not yet been properly investigated and remains one of the poorly studied issues of hydrology. Assessment of the chemical denudation intensity in the Azerbaijan mountain regions has been carried out on the basis of the summed up material on ions runoff over the 1980-2013 period. Value of the average annual wash-out from the catchment area (relation of the average annual ions runoff volume to the catchment area) has been used as an indicator of the chemical denudation intensity. The chemical denudation intensity has been made on the basis of the data on the ions runoff transferred by the rivers. The river water ion runoff module dependence on the catchment average height has been obtained. It has been found that the chemical denudation intensity at the Greater and the Lower Caucasus is increasing with altitude. In contrast, in Talysh the chemical denudation intensity is decreasing with altitude. It has been stated that the role of chemical denudation on the territory under study is substantial (22.6 %), its intensity is nearly six times higher the average world value.

Gamma exposure due to building materials in a residential building at Peruíbe, São Paulo, Brazil

It is well known that most building materials contain traces of natural radionuclides. Exposure in dwellings depends on the concentration of building materials and soil down building. The aim of this study is to determine the activity concentrations of 226Ra, 232Th and 40K in materials and construction products used in the construction of a multistoried building in Peruibe, Sao Paulo, Brazil by high-resolution gamma-ray spectrometry. The results show that the building materials analyzed present activity concentration within the range of average world values, except for clay bricks and sand. The building materials analyzed are within the recommended safety dose limit and do not pose any significant source of radiation hazard.

Improved nonsinglet QCD analysis of fixed-target DIS data

Deep inelastic scattering data on F2 structure function obtained by BCDMS, SLAC and NMC collaborations in fixed-target experiments are analyzed in the non-singlet approximation with next-to-next-to-leading-order accuracy. The strong coupling constant is found to be , which is seen to be well compatible with the average world value. The results, obtained in the present paper by carrying out fits similar to what were performed in (B G Shaikhatdenov et al 2010 Phys. Rev. D 81 034008), with the exception for systematic errors in BCDMS data taken into account in a different way, confirm our previous ones derived in that same paper. This study is also meant to at least partially explain differences in the latest predictions for LHC observables, caused by usage of different sets of parton distribution functions obtained by different groups.

Strong coupling constant from QCD analysis of the fixed-target DIS data

Deep inelastic scattering data on F2 structure function obtained in fixed-target experiments were analyzed in the valence quark approximation with a next-to-next-to-leading-order accuracy. The strong coupling constant is found to be αs (MZ2) = 0.1157 ± 0.0022 (total experimental error), which is seen to be well compatible with the average world value. This study is meant to at least partially explain differences in the predictions for observables at the LHC found recently, caused by usage of various sets of parton distribution functions obtained by different groups.

Study of radon exhalation from soil to ascertain the elevated levels of background radiation of Bangladesh

The outdoor environmental background radiation level in normal area of Bangladesh ranged between 110 and 445 nGy.h1 was observed in a countrywide background radiation survey using P-y radiation survey meter. The United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported to the united Nations General Assembly in its 1988 report that the outdoor country averaged environmental background radiation level in air in 23 countries representing about one half of the world population were found to range between 24 and 85 nGy.h1, with a mean value of 55 nGy.h'1, which is one fourth of the radiation dose Jevel of Bangladesh. In the present study, activity concentration of radium and radon radionuclides was measured in the soil samples of the country and measured their radon emanation coefficient, and radon mass exhalation and radon area exhalation rates with an aim to evaluate the cause of high background radiation level in Bangladesh. The result shows that the concentration of 226 Ra in most of the soil samples was higher than that of world average value, and the concentration of ^Ra, a daughter of U2 Th-series, is more than two times higher than the world average value. The activity of 40K was found higher than both the range and average world value in most of the samples. The results of m Rn emanation coefficients, 222 Rn mass and area exhalation rates are very significant. Values of radon emanation coefficients for the soil samples in a number of locations were found in excess of world average value. The m Rn emanation coefficients was found in the range 3.10 - 44.68%, the mass exhalation rates was found in the range 2.50 - 27.84 uBq.kg'.sec', and the area exhalation rates was found in the range 3.15 - 38.15 mBq.mJ.sec'. Due to high concentrations of radium and potassium in soil and the high radon exhalation rate the external and internal doses are also higher. The total external dose from soil was found higher than the reported results of most of the countries of the World. This result would be helpful to assess the radiation exposure to human, animal and plants, and radiation related cancer risk.

Natural radioactivity and radon exhalation rates in building materials used in Egypt

Natural and fabricated building materials commonly used in Egypt were surveyed for both natural radionuclides content and radon exhalation rate. These include raw as well as construction products. Concentration of natural radionuclides in all samples were determined by γ-ray spectroscopy with HPGe detector. For Radon exhalation rate measurements of fabricated samples, the seal can-technique has been applied using CR-39 plastic track detectors. The radiation hazard indices of the total natural radioactivity in the studied samples were estimated. The results were compared with the corresponding results of different countries and were found to be lying within the average world values. Radon exhalation rate in the studied samples varied between 197 (cement brick) and 907 mBq m −2 h −1 (blast furnace slag cement). The results of this survey suggest that, using blast furnace slag cement for pre-coating the internal walls of buildings in the Urban region of Egypt is discouraged and the replacement of clay brick by cement brick will be more healthy for the public.