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Showing papers in "World Journal of Nuclear Science and Technology in 2019"


Journal ArticleDOI
TL;DR: The comparison of these values to those from Abidjan and other countries, shows that radiology technicians can make efforts to choose radiological parameters to reduce ESD and that radiological technicians must use convenable the X-rays tube to reduce DAP.
Abstract: Our study aims to determine diagnostic reference levels (DRL) for chest front examination in postero anterior (PA) for optimizing patient entrance surface dose (ESD) and dose-area product (DAP) of patients in west of Cote d’Ivoire. 90 patients from three hospitals undergoing conventional radiology were considered. The ESD and DAP for each patient were obtained during chest radiography (PA) examination. The measurements were performed with the device call Dose-Area Product-meter (DAP-meter) with brand Diamentor M4-KDK, type 11017. The DRL were obtained in applying the 75th percentile statistical method to the obtained ESD and DAP. The obtained DRL in ESD for chest radiography for all rooms is 0.40 mGy and in DAP is 54.85 cGy⋅cm2. Our DRL for ESD is higher than those obtained in Abidjan District and in other countries like UK and Cameroon. Our DRL for DAP is higher than those from Abidjan and all other countries for which a similar study was made. The comparison of these values to those from Abidjan and other countries, shows us that radiology technicians can make efforts to choose radiological parameters to reduce ESD. They must use convenable the X-rays tube to reduce DAP by reducing the patient exposure surface.

7 citations


Journal ArticleDOI
TL;DR: In this article, a comparative analysis of different parameters such as enthalpy, moderator temperature, moderator density, flow velocity, pressure, and fuel temperature profile at the fuel pin cell level of PWR is presented.
Abstract: This paper presents a comparative analysis of different parameters such as enthalpy, moderator temperature, moderator density, flow velocity, pressure, and fuel temperature profile at the fuel pin cell level of PWR. Moreover, in this paper pitches to fuel pin radius ratio are varied from 2.3 to 4. The methods and implementation strategy are such that the coupled neutronic and thermal-hydraulic analysis is executed in a fully one dimensional (1D) manner. The thermal hydraulic is based on moderator/coolant mass and enthalpy equation together with one group diffusion equation for fuel pin. Modelling of fuel pin cell and subchannel is executed in two steps. First, the governing equations are derived assuming that all the parameters appearing in the equations are temperature independent. Fuel pin centerline temperature and radially averaged temperature equations are derived from Fourier laws of thermal conductivity. Finally, diffusion coefficient, fission cross-section and absorbing cross-section are evaluated with respect to the fuel pin temperature. The outcome will be helpful for further neutronics and thermal analysis of PWR. Thermal hydraulics parameter varies the maximum 30 percentage from the lowermost value.

5 citations


Journal ArticleDOI
TL;DR: ToSPACE as discussed by the authors is a 3D-based pipe wall thinning management program for nuclear power plants, which includes database buildup, development of FAC and erosion evaluation theories, data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc.
Abstract: A number of piping components in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, SPE (Solid Particle Erosion), LDIE (Liquid Droplet Impingement Erosion), etc. Those mechanisms may lead to thinning, leak, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 of USA in 1986 and in Mihama unit 3 of Japan in 1994, the pipe wall thinning management has emerged as one of the most important issues in nuclear power plants. To manage the pipe wall thinning in the secondary system, Korea has used a foreign program since 1996. As using the foreign country’s program for long term, it was necessary to improve from the perspective of the users. Accordingly, KEPCO-E & C has started to develop the 3D-based pipe wall thinning management program (ToSPACE, Total Solution for Piping And Component Engineering management) from eight years ago, and the development was successful. This paper describes the major functions included in ToSPACE program, such as 3D-based DB (Database) buildup, development of FAC and erosion evaluation theories, UT (Ultra-sonic Test) data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc. ToSPACE program was developed to allow site engineers performing the selection of inspection quantity at each refueling outage, UT data reliability analysis, UT evaluation, determination of next inspection timing, identification of the inspecting and replacing components in 3D drawings, etc., to access easily.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the natural radionuclides in soil and sand have been measured by using high purity germanium (HPGe) detector, and radon exhalation rate was measured by Alpha GUARD.
Abstract: In this study, the natural radionuclides in soil and sand have been measured by using high purity germanium (HPGe) detector. While, radon exhalation rate has been measured by Alpha GUARD. The data analysis is performed to determine 226Ra, 232Th, and 40K activity concentrations in addition to 222Rn exhalation rate. The values of radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and absorbed dose rate were ranged from 46.46 to 124.16 Bq⋅kg−1, 0.07 to 0.33 Bq⋅kg−1, 0.09 to 0.42 Bq⋅kg−1, and 13.24 to 58.37 nGy⋅h−1 respectively in all samples. The area and mass exhalation rates were increased from 9.16 ± 2.83 to 16.18 ± 2.83 Bq⋅m−2⋅h−1 and 1.8 ± 1.34 to 11.35 ± 0.98 Bq⋅kg−1⋅h−1 respectively.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the authors considered a variant of TPCs transportation to the special site after the SRU has been reloaded into the long storage tank (LST) filled with quickly solidifying liquid lead, in which the conditions for coolant natural circulation and heat removal via the tank vessel to the water cooling system are provided.
Abstract: Experience of operating reactor facilities (RF) with lead-bismuth coolant (LBC) has revealed that it is possible to perform safe refueling in short terms if the whole core is replaced and a kit of the special refueling equipment is used. However, comparing with RFs of nuclear submarines (NS), in which at the moment of performance of refueling the residual heat release is small, at RF SVBR-100 in a month after the reactor has been shut down, at the moment of performance of refueling the residual heat release is about 500 kW. Therefore, it is required to place the spent removable unit (SRU) with spent fuel subassemblies (SFSA) into the temporal storage tank (TST) filled with liquid LBC, in which the conditions for coolant natural circulation (NC) and heat removal via the tank vessel to the water cooling system are provided. After the residual heat release has been lowered to the level allowing transportation of the TST with SRU in the transporting-package container (TPC), it is proposed to consider a variant of TPCs transportation to the special site. On that site after the SRU has been reloaded into the long storage tank (LST) filled with quickly solidifying liquid lead, the TPCs can be stored during the necessary period. Thus, the controlled storage of LSTs is realized during several decades untill the time when SNF reprocessing and NFC closing are becoming economically expedient. On that storage, the four safety barriers are formed on the way of the release of radioactive products into the environment, namely: fuel matrix, fuel element cladding, solid lead and steel casing of the LST.

3 citations


Journal ArticleDOI
TL;DR: In this article, the gamma ray spectroscopy using a high purity germanium was used to evaluate the terrestrial gamma radiation level by detector in selected regions of Mali, which revealed that the activity concentrations of naturally occurring 226Ra, 232Th and 40K radionuclides ranges between respectively 17.26 ± 1.81 and 105.43 ± 10.36; 20.41 ± 2.52 and 180.85 ± 19.69; 41.33 ± 8.26 and 627.62 Bq⋅kg−1.
Abstract: This is the first time that a study applies the gamma ray spectroscopy using a high purity germanium to evaluate the terrestrial gamma radiation level by detector in selected regions of Mali. The results reveal that the activity concentrations of naturally occurring 226Ra, 232Th and 40K radionuclides ranges between respectively 17.26 ± 1.81 and 105.43 ± 10.36; 20.41 ± 2.52 and 180.85 ± 19.69; 41.33 ± 8.26 and 627.63 ± 85.62 Bq⋅kg−1. The measures of radium equivalent activity (Raeq), absorbed dose rates (ADR), annual effective dose rate (AEDR), external hazard index (Hex), internal hazard index (Hin) and excess lifetime cancer risk (ELCR) were evaluated. Some of the obtained values exceed the recommended safe levels. Further studies are necessary to constitute a baseline reference data about the terrestrial radiation in Mali.

2 citations


Journal ArticleDOI
TL;DR: The performance audit is to assess the inhomogeneity of TLD sensitivity, repeatability and reproducibility, linearity, energy dependence, angular dependence, and fading, and the obtained data encourage the use of the system for the routine evaluation of the external exposure of workers under ionizing radiation in the authors' laboratory.
Abstract: The objective of this work is to check the dosimetric performances of the TLD-100 as stated by the manufacturer as well as the technical standards of radiation protection. The purpose of the performance audit is to assess the inhomogeneity of TLD sensitivity, repeatability and reproducibility, linearity, energy dependence, angular dependence, and fading. All tests were performed under the conditions of ambient temperature and relative humidity recommended by the manufacturer. We began the study by calibrating the Harshaw 6600 Plus, and checking its performance. The TLD-100 performance verification results were all acceptable and in accordance with the manufacturer’s advertised values and the radiation protection technical standards. However the performance of the TLD-100 that we have evaluated may have some limitations; these limits, which are sources of uncertainty, have been taken into account in this work by evaluating the overall uncertainty of the Hp (10) dose in the uncertainty range 9.45% to 15.80% by simple formulas. The TLD-100 personal dosimeters and the 6600 Plus reader system indicate that the calculated values of the overall uncertainty Hp (10) are well below the allowable values of 21% to 42% suggested for personal dosimetry services. The obtained data encourage the use of the system for the routine evaluation of the external exposure of workers under ionizing radiation in our laboratory.

2 citations


Journal ArticleDOI
TL;DR: In this paper, a new formulation for the calculation of the mass flux was proposed, in such a way to remove both of these drawbacks. But, it is only valid for the specific range of data for what it was created, and it does not allow the analytical evaluation of the heat transfer coefficient from the extension equation.
Abstract: Correlations for the extension of a water vapor jet injected in a liquid pool were historically proposed considering the mass flux (kg/m2/s) as a constant. The results were satisfactory, however adjusting the values by linear regression. Although, it presents the following drawbacks: 1) the formulation is only valid for the specific range of data for what it was created; 2) it does not allow the analytical evaluation of the heat transfer coefficient from the extension equation. This paper proposes a new formulation for the calculation of the mass flux, in such a way to remove both of these drawbacks.

1 citations


Journal ArticleDOI
TL;DR: The relationship between coal quality and enrichment factors for the radionuclides of interest (K40, Ra226, Th232 and Po210) in coal combustion residues from three South African coal-fired power plants (CFPP) was investigated in this article.
Abstract: Coal-fired power plants (CFPP) provide approximately 40% of the world’s energy demand. Naturally occurring radioactive materials (NORM) contained in coal become enriched in coal combustion residues as a result of the elimination of carbon during combustion. The fly ash and bottom ash produced from CFPP may be significant sources of exposure to naturally occurring radionuclides for the population near the combustion plant or ash dumps. Despite this fact, very few studies have actually addressed the relationship of the NORM enrichment factors and the quality of coal used. This paper aims to relate the quality of coal to the enrichment factors for the radionuclides of interest (K40, Ra226, Th232 and Po210) in coal combustion residues from three South African CFPP. The data from other CFPP was also taken into account to establish this correlation. The feedstock coal used in these CFPP is typically low quality, with ash content in the range of 25 - 45 wt%. The radionuclides investigated were determined by gamma spectrometry with the exception of Po210, which was determined by alpha spectrometry. The enrichment factors for the radionuclides of K40, Ra226, Th232 and Po210 in the fly ash and bottom ash (except Po210) was found to be directly proportional to the quality of coal. That is when the ash percentage increased (coal quality decreased) the enrichment factor decreased. The Po210 radionuclide in the bottom ash had an enrichment factor less than one. The relationship between coal quality and enrichment factors for the radionuclides of K40, Ra226, Th232 and Po210 in both the fly ash and bottom ash (except Po210 in the bottom ash) was demonstrated by the following mathematical equation: . This equation may be used as a good indication in obtaining an estimate in determining the enrichment of the mentioned radionuclides in coal combustion products such as fly ash and bottom ash.

1 citations


Journal ArticleDOI
TL;DR: In this article, a new method for the identification of the chemical Elements isotopes takes advantage of the isotope Neutron Excess (NE) number, and the representation of the natural isotopes in the Z-NE plane reveals a surprising correspondence between atom's nuclear and electronic structures.
Abstract: A new method for the identification of the chemical Elements isotopes takes advantage of the isotope Neutron Excess (NE) number. The repre-sentation of the natural isotopes in the Z-NE plane reveals a surprising correspondence between atom’s nuclear and electronic structures. Nuclear directs the atom electronic structure in spite of the alternative set of numbers ruling the two main atom’s compartments. These compartments appear better integrated than actually considered. The Mendeleev periodic table is rooted in the atom’s nuclear structure. Two recent studies arrive to identical conclusions.

1 citations


Journal ArticleDOI
TL;DR: In this article, a brief review of present status of radiotracer and nucleonic gauges techniques as applied to polish industry is presented, including the application of beta radiation-based gauges for air borne fly ash monitoring and radiation technology for flue gas treatment are the examples of using this technique in power sector equipped with coal and oil fired boilers.
Abstract: Nuclear and radiation technologies play an important role in Polish power sector, oil industry and mining sector, starting from fossil fuels exploitation, their transport and distribution and finally power generation. Application of environmental isotopes, stable and radioactive, in ground water monitoring in the vicinity of open cast lignite mine, and radon monitor applied for miner’s safety in deep coal mines and nucleonic control systems for ash in coal quality control is often used in mining industry. Other applications of nuclear techniques reviewed, concern the oil industry, oil field recovery, transportation pipelines and refineries. Finally, the application of beta radiation-based gauges for air borne fly ash monitoring and radiation technology for flue gas treatment are the examples of using this technique in power sector equipped with coal and oil fired boilers [1]. The radiotracers techniques were used also in glass industry (determination and optimization parameters of the furnaces), cement industry (test of aggregates for the production of cement and optimization media transport in pipelines), metallurgy of Cu, Pb, Zn (investigation of pyrometallurgy processes and new techniques), cellulose industry, environmental and (mainly hydrological) research etc. [2]. The article is brief review of present status of radiotracer and nucleonic gauges techniques as applied to polish industry.

Journal ArticleDOI
TL;DR: In this paper, the authors present a report about the research carried out in the Extractive Metallurgy Area of the Department of Advanced Materials of CChEN, whose objective is to know the behavior of the thorium element when the mineral carrier is leached.
Abstract: The existence of the thorium element in the ores from the Atacama region, Chile, and its importance in the activities of the nuclear industry, have generated the interest of the Chilean Nuclear Energy Commission (CChEN) to study the technical feasibility of its recovery, like ThO2 through the implementation of hydrometallurgical techniques, such as leaching, solvent extraction, among others. The present work has become a report about the research carried out in the Extractive Metallurgy Area of the Department of Advanced Materials of CChEN, whose objective is to know the behavior of the thorium element when the mineral carrier is leached. The leaching tests were carried out in a glass reactor in batch mode, by mechanical agitation, varying different operational parameters, such as: type of leaching solution, concentration of acid in the solution, system temperature and granulometry of the mineral. The results indicate that there is technical feasibility for the recovery of thorium by leaching the mineral carrier with hydrochloric and/or sulfuric solution. The highest recovery of thorium for a sulfuric solution was 70.0% and for a hydrochloric solution of 83.8%, so the process presents a good efficiency in both cases. For a hydrochloric solution, the mathematical model of the thorium recovery efficiency obtained is: Y=31.14+26.25*X1+8.69*X2−0.82*X3+9.5*X12−0.83*X13−3.71*X23−1.83*X123+6.45 The concentration of HCl and temperature, as well as their interaction, significantly affect the recovery of thorium for Sierra Indiana mineral, as well as temperature and granulometry. The previous model gives a good representativeness of 99.98%. For a sulfuric solution, the mathematical model of the thorium recovery efficiency obtained is: Y=29.78+25.92*X1+0.99*X2−1.05*X3−2.05*X12−9.84*X13−5.26*X23−3.87*X123+15.18 The model indicates that the recovery of thorium for the mineral is significantly affected by the concentration of sulfuric acid, and to a lesser degree by the temperature and granulometry. The model provides a representativeness of 98.3%.