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Showing papers in "World Journal of Nuclear Science and Technology in 2015"


Journal ArticleDOI
TL;DR: In this paper, the authors considered that the time derivative for neutron current density is not negligible in the P1 equation and derived a new system of point kinetics that they named as modified.
Abstract: The system of point kinetics equations describes the time behaviour of a nuclear reactor, assuming that, during the transient, the spatial form of the flux of neutrons varies very little. This system has been largely used in the analysis of transients, where the numerical solutions of the equations are limited by the stiffness problem that results from the different time scales of the instantaneous and delayed neutrons. Its derivation can be done directly from the neutron transport equation, from the neutron diffusion equation or through a heuristics procedure. All of them lead to the same functional form of the system of differential equations for point kinetics, but with different coefficients. However, the solution of the neutron transport equation is of little practical use as it requires the change of the existent core design systems, as used to calculate the design of the cores of nuclear reactors for different operating cycles. Several approximations can be made for the said derivation. One of them consists of disregarding the time derivative for neutron density in comparison with the remaining terms of the equation resulting from the P1 approximation of the transport equation. In this paper, we consider that the time derivative for neutron current density is not negligible in the P1 equation. Thus being, we obtained a new system of equations of point kinetics that we named as modified. The innovation of the method presented in the manuscript consists in adopting arising from the P1 equations, without neglecting the derivative of the current neutrons, to derive the modified point kinetics equations instead of adopting the Fick’s law which results in the classic point kinetics equations. The results of the comparison between the point kinetics equations, modified and classical, indicate that the time derivative for the neutron current density should not be disregarded in several of transient analysis situations.

13 citations


Journal ArticleDOI
TL;DR: If it is possible to ensure more energy efficient production of enriched uranium, improved nuclear fuels and reactors that allow greater utilization, extended life times for nuclear power plants (NPPs) that reduce the need to build new facilities, improved coding system capable of minimizing the discrepancy between theoretical and experimental calculation of spallation products, improved data library with sufficiently available high energy nuclear data to perform a better coding analysis, and finally, considering the environmental safety if the disposal of the radioactive wastes could manage more effectively
Abstract: This paper reflects the scopes of accelerator driven system (ADS) based nuclear energy, as a reliable source of electric energy generation, comparing to the other existing non-renewable and renewable sources. There are different limitations in the use of every source of electric energy but in consideration of minimum environmental impact, exclusively inherently low greenhouse gas (GHG) emission, and also, high life time with maximum power production efficiency, nuclear would be the best choice. From this study it was found that several difficulties involved in the ADS based energy production, more specifically, difficulties regarding the target parameters, coding system, waste management, etc. Hence suggestions from this study points out that if it is possible to ensure more energy efficient production of enriched uranium, improved nuclear fuels and reactors that allow greater utilization, extended life times for nuclear power plants (NPPs) that reduce the need to build new facilities, improved coding system capable of minimizing the discrepancy between theoretical and experimental calculation of spallation products, improved data library with sufficiently available high energy nuclear data to perform a better coding analysis, and finally, considering the environmental safety if the disposal of the radioactive wastes could manage more effectively, nuclear energy would then play a significant role in minimizing future energy crisis worldwide as well as to save our loving green earth.

12 citations


Journal ArticleDOI
TL;DR: In this article, a carrier-free radioisotope for radiotherapy was developed based on separation of Nd/Pm, Gb/Tb, Dy/Ho and Yb/Lu by extraction chromatography.
Abstract: 149Pm, 166Ho, 161Tb and 177Lu conjugated to chemical agents (monoclonal antibodies, polypeptide, etc.) have the appropriate decay characteristics for imaging and therapeutic studies and consequently the potential to be useful in radiotherapy and diagnosis. These carrier-free radioisotopes can be produced by neutron irradiation of a lanthanide target followed by β- decay, and a posterior radiochemical separation of the daughter radionuclide from macro-amounts of the parent target. In order to produce carrier free 149Pm, 161Tb, 166Ho and 177Lu for radiotherapy, with a radionuclide purity of more than 99.9%, a device production was developed based on separation of Nd/Pm, Gb/Tb, Dy/Ho and Yb/Lu by extraction chromatography.

12 citations


Journal ArticleDOI
TL;DR: In this article, the radon concentration in forty samples of building materials collected from local market in Dakahlia Governorate, Egypt were measured using solid state nuclear track detector and the obtained results have shown that the highest average of radon concentrations in granite samples and the average value is 845.43 Bqm-3, while the lowest average value was white cement 68.42 Bqs-3.
Abstract: In this paper, forty samples of building materials collected from local market in Dakahlia Governorate, Egypt. The radon concentration in these samples were measured using solid state nuclear track detector. Solid state nuclear track detectors have become an important tool in every investigation of the radon levels in the surrounding environment. The obtained results have shown that the highest average of radon concentration in granite samples and the average value is 845.43 Bqm-3, while the lowest average value is white cement 68.42 Bqm-3. The present work is important to detect any harmful radiation in our houses that affect human and to establish a data base for building materials which, used in a local market. The obtained results show that the radon concentrations of the most samples are below the allowed limit of ICRP.

11 citations


Journal ArticleDOI
TL;DR: Activity concentrations of primordial radionuclides such as 40 K, 226 Ra and 232 Th were determined in edible mushrooms samples in Ekiti State Nigeria and were found to be below maximum permissible levels.
Abstract: Activity concentrations of primordial radionuclides such as 40 K, 226 Ra and 232 Th were determined in edible mushrooms samples in Ekiti State Nigeria. The edible mushrooms collected are Termitomyces striatus, Psathyrella atroumbonata, Termitomyces robustus, Pleurotus tuber-regium and Pleurotus squarrosulus. The activity measurements were carried out by gamma spectrometry. The average concentrations of 40 K varied from 254.17 ± 46.78 to 416.07 ± 68.43 Bq∙kg −1 , 226 Ra concentrations varied from 2.68 ± 0.82 to 21.64 ± 7.23 Bq∙kg−1 and 232Th concentrations varied from 8.57 ± 3.25 to 10.98 ± 4.31 Bq∙kg−1. The concentrations were converted to effective dose. Effective doses calculated were found to be below maximum permissible levels. Therefore, no health risk is envisaged for those that normally consumed these mushrooms.

11 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a study on the kinetics of the uranium conversion process, consisting in the reduction of uranium trioxide to uranium dioxide using hydrogen gas at temperatures of 500°C, 600°C and 700°C.
Abstract: This article presents a study on the kinetics of the uranium conversion process, consisting in the reduction of uranium trioxide to uranium dioxide using hydrogen gas at temperatures of 500°C, 600°C and 700°C. Hydrogen concentrations used in the flow were 0.25 M, 0.50 M and 0.75 M. The mechanism established for the study of the kinetics of reduction of uranium trioxide was through the formation of an intermediate compound, U3O8. For this reason, these tests were divided into 2 stages: the first one the reduction from UO3 to U3O8, and second one from U3O8 to UO2. The results of each test were quantified by the release of H2O(g) produced by both reactions. Tests showed that the ideal working conditions are for hydrogen concentration flows of 0.75 M and temperatures in the range of 500°C - 600°C, with the intent to decrease the occurrence of side reactions that interfere with the process.

10 citations


Journal ArticleDOI
TL;DR: In this paper, the relative strengths of the interesting (n + 8Be) and (α + 5He) cluster configurations in 9Be were estimated from single measurements where the relationship between the energy and the scattering angle of the observed stable ejectile was constrained by two-body kinematics.
Abstract: The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at the incident energy of 30 MeV. Angular distributions for 9Be(3He, 3He) 9Be, 9Be (3He, 3He) 8Be, 9Be (3He, 7Be) 5He, 9Be (3He, 6Li) 6Li and 9Be (3He, 7Li) 5Li reaction channels were measured. Experimental angular distributions for the corresponding ground states (g.s.) were analyzed within the framework of the optical model, the coupled-channel approach and the distorted-wave Born approximation. Cross sections for channels leading to unbound 5Heg.s., 5Lig.s. and 8Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile was constrained by two-body kinematics. Information on the cluster structure of 9Be was obtained from the transfer channels. It was concluded that cluster transfer was an important mechanism in the investigated nuclear reaction channels. In the present work an attempt was made to estimate the relative strengths of the interesting (n + 8Be) and (α + 5He) cluster configurations in 9Be. The contributions of different exit channels have been determined confirming that the (α + 5He) configuration plays an important role. The configuration of 8Be consisting of two bound helium clusters (5He + 6He) is significantly suppressed, whereas the two-body configurations (n + 8Be) and (α + 5He) including unbound 8Be and 5He are found more probable.

10 citations


Journal ArticleDOI
TL;DR: In this article, the main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047).
Abstract: Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047). These techniques were used to improve the metallurgical bonding between the UMo and the cladding by rolling. Finally, design parameters and manufacture of UMo plate fuels were established. Mechanical tests were used to characterize the plates, resulting in UTS values of about 700 and 1000 MPa for the UMo alloys. These results are complemented with metrological analyses, X-Ray diffraction (XRD), thermal analyses, and metallography. X-rays and ultrasound scanners were used to monitor bonding and the co-rolling effects. These initial results show the main obstacles to the engineering development of UMo monolithic plate fuels with Al-6061 cladding, and these are discussed herein.

8 citations


Journal ArticleDOI
TL;DR: In this paper, the specific requirements which must be met by the NPT proposed for use in developing countries are formulated, basic statements of the SVBR100 concept are presented, design and principal scheme of the reactor fa-ility are described, major characteristics of SVBR-100 are summarized.
Abstract: Many developing countries need ecologically clean power sources (PS). The nuclear power plants are such sources. However, a great number of the developing countries do not possess developed large capacity power systems. Moreover, currently in the developing countries, there are no highly skilled personnel to provide construction and reliable and safe operation of the nuclear plants, which are complex and potentially hazardous systems. In some countries, the level of terroristic threat is extremely high. For that reason, there are specific requirements to the nuclear PSs intended for use in the developing countries. In the presented report, the specific requirements which must be met by the NPT proposed for use in developing countries are formulated, basic statements of the SVBR-100 concept are presented, design and principal scheme of the reactor fa-ility are described, major characteristics of SVBR-100 are summarized.

7 citations


Journal ArticleDOI
TL;DR: In this paper, an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR was carried out under various atmospheric conditions.
Abstract: For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under various atmospheric conditions. In a steam atmosphere, it was assessed that UO2 would not be fully oxidized into U3O8 due to the relatively lower oxygen partial pressure, while UO2 will be fully oxidized into U3O8 in an air atmosphere. In an air and steam mixture atmosphere, the UO2 oxidation was dominantly affected by the air volumetric fraction, because of the relatively higher oxygen partial pressure of air. In addition, the effect of H2 volumetric fraction on the oxygen partial pressure under a mixture atmosphere was calculated, and it was revealed that UO2 pellet oxidation could be reduced above the critical value of H2 volumetric fraction.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the modeling and simulation of flashing-induced instabilities in natural circulation systems, with special emphasis on simplified boiling water reactors (SBWRs), have been studied by using an experimental test facility (SIRIUS-N) and RELAP5/MOD3.2 thermal hydraulic code.
Abstract: This paper reports on the modeling and simulation of flashing-induced instabilities in naturalcirculation systems, with special emphasis on simplified boiling water reactors (SBWRs). In this work, flashing-induced oscillations have been studied by using an experimental test facility (SIRIUS-N) and RELAP5/MOD3.2 thermal hydraulic code. The behavior of the test facility is investigated for different values of core inlet temperature value. The results of the simulations have been compared qualitatively and quantitatively with experiments. In general, deviations are found between the numerical and experimental results, in spite of the close similarity between the SIRIUS-N facility and the definition of the system in the RELAP code. This result indicates that predictions regarding experimental facility, based on modeled system, should be carefully considered.

Journal ArticleDOI
TL;DR: In this article, the authors showed that the efficiency of valence stabilization depends on the amount and chemical structure of the added compounds, such as aliphatic alcohols, aldehyds or acids prior to irradiation.
Abstract: Valence stabilization of polyvalent ions in acidic solutions during gamma irradiation is an important issue in nuclear aqueous chemical technology. Radiolysis and self irradiation problems encountered during chemical reprocessing of nuclear fuel or during chemical separation of transuranium elements or fission products are extremely important. Consequently studies on valence stabilization of polyvalent ions in strong gamma irradiation fields are very useful. In our previous publications, the valence stabilization of Fe(II) ions in acidic solutions during continuous gamma irradiation was achieved by using an inorganic compound; such as sodium sulfite, or some organic additives such as aliphatic alcohols, aldehyds or acids prior to irradiation. It was found that the efficiency of valence stabilization depends on the amount and chemical structure of the added compounds. In the present work, valence stabilization of divalent iron during gamma irradiation was studied in presence of some organic additives, belonging to some other classes of organic compounds such as Phenol (aromatic alcohol), Acetone (aliphatic ketone), 4-Aminopyridine (heterocyclic amino compound) and Hydrazine hydrate (aliphatic amino compound) to complement our previous studies. The results showed that valence stabilization of Fe(II) in presence of these compounds depends also on the amount and chemical structure of the additive used. Some interaction mechanisms have been proposed.

Journal ArticleDOI
TL;DR: The purpose of this work is to perform a critical analysis of the Fukushima nuclear accident, focusing at the common cause failures produced by tsunami, as well as anAnalysis of the main redundant systems.
Abstract: The Fukushima nuclear accident has generated doubts and questions which need to be properly understood and addressed. This scientific attitude became necessary to allow the use of the nuclear technology for electricity generation around the world. The nuclear stakeholders are working to obtain these technical answers for the Fukushima questions. We believe that, such challenges will be, certainly, implemented in the next reactor generation, following the technological evolution. The purpose of this work is to perform a critical analysis of the Fukushima nuclear accident, focusing at the common cause failures produced by tsunami, as well as an analysis of the main redundant systems. This work also assesses the mitigative procedures and the subsequent consequences of such actions, which gave results below expectations to avoid the progression of the accident, discussing the concept of sharing of structures, systems and components at multi-unit nuclear power plants, and its eventual inappropriate use in safety-related devices which can compromise the nuclear safety, as well as its consequent impact on the Fukushima accident scenario. The lessons from Fukushima must be better learned, aiming the development of new procedures and new safety systems. Thus, the nuclear technology could reach a higher evolution level in its safety requirements. This knowledge will establish a conceptual milestone in the safety system design, becoming necessary the review of the current acceptance criteria of safety-related systems.

Journal ArticleDOI
TL;DR: In this paper, a study of the compound multiplicity characteristics of 14.6 and 200 AGeV/c 28 Si and 32 S-emulsion interactions has been performed.
Abstract: This work displays a study of the compound multiplicity characteristics of 14.6 and 200 AGeV/c 28 Si and 32 S-emulsion interactions, where the number of shower and grey particles taken together is termed as compound multiplicity, Nc. It has been found that the average compound multiplicity depends on the mass number of the projectile, Ap, and energy of the projectile. A positive linear dependence of the compound multiplicity on the black, grey, heavy and shower particles has been found. Also the scaling of compound multiplicity distributions produced in these interactions has been studied in order to check the validity of KNO-scaling. A simplified universal function has been used to represent the experimental data. The experimental results have been compared with those obtained by analyzing events generated with the computer code FRITIOF based on Lund Monte Carlo model.

Journal ArticleDOI
TL;DR: In this article, the authors focused on assessing radiation doses caused by radioactive substances released from the nuclear power plant (NPP) Ninh Thuan 1 under the scenario of normal operation using software package NRCDose72 provided by the USNRC.
Abstract: Based on guides RG 1.109, RG 1.111 published by United States Nuclear Regulatory Commission (USNRC), our research concentrates in assessing radiation doses caused by radioactive substances released from the nuclear power plant (NPP) Ninh Thuan 1 under the scenario of normal operation using software package NRCDose72 provided by the USNRC. The database including the released radioactive nuclides, meteorology, terrain, population and agricultural production activities have been collected and processed to build the input data for the model calculation. The wind rose distribution obtained from the meteorological data in a five-year period from 2009-2013 showed that the radioactive nuclides released to environment spread in two main wind directions which are North East and South West. The X/Q (s/m3) and D/Q (s/m2) qualities which are, respectively, the ratio of activity concentration to release rate and that of deposition density of radioactive nuclides to release rate were calculated within an area of 80 km radius from the NPP site using XOQDOQ. Population doses were calculated using GASPAR. The XOQDOQ and GASPAR are two specific softwares in NRCDose72 package.

Journal ArticleDOI
TL;DR: In this article, a supercritical water-cooled fast-reactor (SCFR) was analyzed and the sensitivities of assembly parameters, core arrangements and fuel nuclide components to the breeding ratio were analyzed.
Abstract: The purpose of the study is to analyze the breeding ratio of a supercritical water cooled fast reactor (SCFR) and to increase the breeding core of SCFR. The sensitivities of assembly parameters, core arrangements and fuel nuclide components to the breeding ratio are analyzed. In assembly parameters, the seed fuel rod diameter has higher sensitivities to the conversion ratio (CR) than the coolant tube diameter in blanket. Increasing heavy metal fraction is good to CR improvement. The CR of SCFR also increases with a reasonable core arrangement and Pu isotope mass fraction reduction in fuel, which can achieve more negative coolant void reactivity coefficient at the same time. The breeding ratio of SCFR is 1.03128 with a new core arrangement. And the coolant void reactivity coefficient is negative, which achieves a fuel breeding in initial fuel cycle.

Journal ArticleDOI
TL;DR: In this paper, a new approach to solving the observation of enhanced neutron production in high-energy heavy ion induced reactions in thick targets is presented, where two different reaction mechanisms in these interactions are considered: 1) Limited fragmentation of the projectile, called SPALLATION; 2) Complete nuclear fragmentation, referred to as BURST, were considered.
Abstract: A new approach to solving the observation of enhanced neutron production in high-energy heavy ion induced reactions in thick targets is presented. Two different reaction mechanisms in these interactions are considered: 1) Limited fragmentation of the projectile, called SPALLATION; 2) Complete nuclear fragmentation of the projectile fragment into individual relativistic hadrons only, referred to as “BURST”. The abundance of this second path increases with the charge and energy of the projectile and may be responsible for enhanced neutron production observed with radiochemical methods in 44 GeV 12C and 72 GeV 40Ar irradiations. Interactions of 72 GeV 22Ne in nuclear emulsions show that SPALLATION and BURST have strongly different interaction signatures, and also that the rate of BURSTS increases from (26 ± 3)% of all interactions in the 1st generation to (78 ± 6)% in the 2nd generation. Further experimental signatures of BURSTS will be described; however, no model based on physics concepts can be presented. This effect may have practical consequences for neutron safety considerations in the construction of advanced heavy ion accelerators.

Journal ArticleDOI
TL;DR: The epithermal neutron shape factor (α) was determined in the permanent cadmium lined irradiation channel installed in the large outer irradiation site of the Nigeria Research Reactor-1 (NIRR-1) by the Cadmium covered multimonitor method using the monitors Al-01% Au, Zr and Zn thin foils and Mo thin wire and was found to be -0137 ± 0018 as mentioned in this paper.
Abstract: The epithermal neutron shape factor (α) was determined in the permanent cadmium lined irradiation channel installed in the large outer irradiation site of the Nigeria Research Reactor-1 (NIRR- 1) by the cadmium covered multimonitor method using the monitors Al-01% Au, Zr and Zn thin foils and Mo thin wire and was found to be -0137 ± 0018 The high negative value of α indicates a hardened epithermal neutron spectrum in the cadmium lined irradiation channel The α value obtained was used in the single comparator method of ENAA (ko-ENAA) for the determination of the concentrations of elements in the standard reference material NIST 1515 Apple leaves using Al-01% Au thin foil as the single comparator The concentrations of the elements Sm and Br were determined in the NIST 1515 Apple leaves because of their high Qo values and are in good agreement with the certified values

Journal ArticleDOI
TL;DR: In this paper, the major, minor and trace elements of the food legumes, cowpeas (Vigna unguiculata), soya beans (Glycine max), and groundnuts (Arachis hypogaea) collected from rural farmers in four rural villages around Zaria, Nigeria were analysed for the concentrations of the major and minor elements by the ko-ENAA and INAA methods.
Abstract: Samples of the food legumes, cowpeas (Vigna unguiculata), soya beans (Glycine max) and groundnuts (Arachis hypogaea) collected from rural farmers in four rural villages around Zaria, Nigeria were analysed for the concentrations of the major, minor and trace elements by the ko-ENAA and INAA methods. Irradiation and γ-ray counting were performed using the NIRR-1 and associated facilities. The NIST 1515 Apple leaves were used as the quality control material. The concentrations of the elements Se, Br and Rb were determined by ko-ENAA while those of Na, K, Zn, La, Br, Sm and Sc were determined in INAA in the food legumes. The concentrations of Zn found in all the legumes are within the limit specified in international guidelines. The concentrations of Se found in the food legumes are above the limit specified in international guidelines. The food legumes are good sources of the elements Na, K, Zn which can meet adequate dietary requirements provided the legumes are not refined. Bromine is not at toxic levels in the food legumes.

Journal ArticleDOI
TL;DR: In this paper, the authors present theories used in solid-state nuclear magnetic resonance (NMR) and spectrum-spectroscopy (Spectroscopy) to solve the time-dependent Schrodinger equation.
Abstract: This short review article presents theories used in solid-state nuclear magnetic resonance spectroscopy. Main theories used in NMR include the average Hamiltonian theory, the Floquet theory and the developing theories are the Fer expansion or the Floquet-Magnus expansion. These approaches provide solutions to the time-dependent Schrodinger equation which is a central problem in quantum physics in general and solid-state nuclear magnetic resonance in particular. Methods of these expansion schemes used as numerical integrators for solving the time dependent Schrodinger equation are presented. The action of their propagator operators is also presented. We highlight potential future theoretical and numerical directions such as the time propagation calculated by Chebychev expansion of the time evolution operators and an interesting transformation called the Cayley method.

Journal ArticleDOI
TL;DR: In this paper, the evaluation of radioactivity and spontaneous fission rates was performed for 8 nuclides from the natural radioactive 238U, 235U and 232Th======decay chains.
Abstract: In this work, the evaluation of natural radioactivity and spontaneous fission rates was performed for 8 nuclides from the natural radioactive 238U, 235U and 232Th decay chains. For this purpose, three samples of structural materials of the neutrino detector, i.e. aluminum, titanium and glass were analyzed by gamma spectroscopy and by neutron activation analysis to quantify a specific radioactivity of the samples. According to the results of this investigation, glass and aluminum samples have maximum values of the mean uranium concentrations 7.3(7) × 10-4% and 3.1(6) × 10-5%, respectively, while the lowest value for mean concentration of the uranium was found in titanium samples to be 4.7(3) × 10-6%. Aluminum sample had maximum values of the mean thorium concentrations, 2.5(8) × 10-3%, while the lowest value for mean concentration of the thorium was found in titanium samples to be 6.2(3) × 10-7%.

Journal ArticleDOI
TL;DR: In this article, XRD spectroscopy results indicate that the major, minor and trace constituents varied from one sample to another Samples were also analyzed by HPGe gamma spectrometer to determine the activity of U-238, Th-232 series and K-40 series.
Abstract: Ten soil samples from Jabal Al Qur, Wadi Baba, and Wadi Sieh in Sinai, Egypt, were analyzed by XRD spectroscopy The XRD spectroscopy results indicate that the major, minor and trace constituents varied from one sample to another Samples were also analyzed by HPGe gamma spectrometer to determine the activity concentration of U-238, Th-232 series and K-40 The concentrations for 238U ranged from 5703 to 422041 Bq/kg with an average 111075 Bq/kg, for 232Th, ranged from 1355 to13046 Bq/kg with an average 7185 Bq/Kg The concentrations for 40K were in the range from 1218 to 94893 Bq/kg with an average value 45709 Bq/kg The average activity concentration values of 226Ra, 232Th, and 40K, in all the collected samples were higher than the world average The radium equivalent (Req), absorbed dose rate (DR), the effective dose rate (Deff), and hazard indices resulted due to the natural radionuclides in soil are also calculated The Results show that the study area is not safe for human and environments

Journal ArticleDOI
TL;DR: Movement of the patient during myocardial perfusion SPECT leads to some artifacts that make the interpretation difficult and this should be considered as a potential source of error in myocardIAL perfusion studies.
Abstract: Movement of the patient during myocardial perfusion SPECT leads to some artifacts that make the interpretation difficult. In this study, myocardial perfusion imaging protocol was performed on a cardiac phantom and SPECT was performed by simulating patient movements. A lesion model with dimensions of 1.2 × 2 × 2 cm was created on the inferoseptal wall of the cardiac phantom. Imaging was done in circular orbits in 64 × 64 matrix and step and shoot mode. First set of images taken with no movement was referred as the reference image. During imaging, patient movement was simulated by moving the phantom in ±X and ±Y directions between the frames starting from 8th frame to 16th frame. At the end of imaging, Bull’s eye maps of images with movement were com-pared with Bull’s eye maps of reference images. Bull’s eye maps were evaluated by an experienced nuclear medicine physician. Shifting patient’s movement in all directions by ±1 and ±2 cm, dis-placed the localization of the lesion mildly and this did not hamper the evaluation. However, movements of ±3 or ±4 cm resulted in artifacts which in turn caused partial or no visualization of the lesion. In motion corrected images, the lesion could be evaluated in ±1 and ±2 cm movements while lesion could not be evaluated in ±3 and ±4 cm movements. As a result, movement greater than ±3 cm causes significant image artifacts and this should be considered as a potential source of error in myocardial perfusion studies.

Journal ArticleDOI
TL;DR: In this article, the authors present results of conducted research based on LCS and comparison of this results with the measurements carried out by Accredited Laboratory for Cali-bration of Dosimetric and Radon Instruments in Central Laboratory for Radiological Protection in Warsaw (CLOR).
Abstract: In accordance with the recommendations of the most recent Directive of Council EURATOM No. 2013/51, which concerns requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption, we are obligated to monitor the level of approximate dose of radioactive substances. The directive indicates two basic isotopes: tritium and radon, which ought to be monitored continuously. Essential are also para-metric values as well as frequency, methods of monitoring of radioactive substances and equipment requirements. Directive states that measurements of content of tritium and radon ought to be taken as well as calculations of approximate dose natural and artificial radionuclides content should be done, apart from tritium, potassium-40, radon and short-living products of radon disintegration. In case if one of radioactive concentrations is over 20% of computational value or concentration of tritium is over parametric value analysis of additional radionuclides is required. A detailed list of radionuclides is presented in appendix No. 3 in the Directive. Laboratory of Nuclear Control Systems and Methods in the Institute of Nuclear Chemistry and Technology (INCT) worked out a Miniature Liquid Scintillation Counter (LCS) [1] [2], within a project titled “New generation of intelligent radiometric devices with cordless transmission of information” (UDA-POIG.01.03.01-14-065/08) co-financed by European Union from the European Regional Development Fund (ERDF). This Miniature Liquid Scintillation Counter may be used as a basic equipment resulting in the above mentioned directive. This article presents results of conducted research based on LCS and comparison of this results with the measurements carried out by Accredited Laboratory for Cali-bration of Dosimetric and Radon Instruments in Central Laboratory for Radiological Protection in Warsaw (CLOR).

Journal ArticleDOI
TL;DR: The results of performance tests proved the high short and long-term stability, the very low leakage current, the low directional dependence and very high ion collection efficiency through the special design of the collecting electrode in this new ring-shaped monitor chamber.
Abstract: Today, dosimeters are used generally for dosimetry of the diagnostic X-ray beam. Ionization chambers are appropriate instruments for monitoring and also the dosimetry of X-ray beam in medical diagnostic equipment. The present work introduces design and investigation of a new ring-shaped monitor chamber with a PMMA body, graphite-coated PMMA windows (0.5 mm thick), a special graphite-foil central electrode (0.1 mm thick, 0.7 g/cm3 dense) that creating two sensitive volumes and a central hole for crossing the radiation beam with less attenuation. The results of performance tests conducted at the Nuclear Science and Technology Research Institute, AEOI in Karaj- Iran proved the high short and long-term stability, the very low leakage current, the low directional dependence and very high ion collection efficiency through the special design of the collecting electrode. Moreover, the FLUKA Monte Carlo simulations certified the negligible effect of central electrode on this new ring-shaped monitor chamber. According to the results of the performance tests, the new monitor chamber can be used as a standard dosimeter in order to monitor X-ray beam in primary standard dosimetry laboratories.

Journal ArticleDOI
TL;DR: In this study, steps to optimize the acquisition method, and to choose a scatter correction, are taken to improve image quality and diagnostic accuracy for planar 67Ga imaging.
Abstract: The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose a scatter correction. First, we acquired individual images from the 93 keV, 185 keV, and 300 keV photopeak; then the images were added together and compared to the individual images. Second, we compared results from a low-medium-energy (LME) collimator with those from a conventional medium-energy (ME) collimator. Also, we examined whether to combine the data from all three of the usual window locations (set about 93 keV, 185 keV, and 300 keV) or to use the data from only two. Third, we compared results from a conventional photopeak ± 10% window with those from a photopeak ± 9 keV window. Fourth, for scatter correction we compared results using the triple energy window (TEW) method with those using the multi-photopeak dual window (MDW) method. The phantoms studied were cold rods in a uniform background, and hot spheres within a cylinder containing uniformly radioactive water. The clinical study involved 22 patients with lung lesions. By the comparison by the contrast ratio in cold rods phantom, 15.6% is improved in LME (2 peaks) than ME (3 peaks), and 3.2% is improved in photopeak ± 9 keV than photopeak ± 10%, 10.2% is improved in TEW than MDW. However, the TEW scatter correction method recognized unstable to the contrast ratio in a clinical study. In addition, a body outline might disappear.

Journal ArticleDOI
TL;DR: In this paper, the authors showed that methanol or formic acid are capable of providing about 80% protection while ethanol or acetaldehyde can provide about 70% protection and Propanol has the least protective effect i.e. about 54%.
Abstract: In gamma irradiated aqueous acidic uranium solutions, tetravalent uranium ions are easily oxidized while U(VI) ions remain unchanged. In general, valence change of polyvalent metallic ions during chemical reprocessing of spent nuclear fuel solutions can lead to undesirable effects under the influence of the existing gamma radiations. Consequently, studies on valence stabilization of Uranium ions during chemical treatment in strong gamma irradiation fields seem to be highly interesting. It has been reported before that some organic compounds proved to be effective in stabilizing the valence of Fe(II) ions during extended gamma irradiation of their acidic solutions. In the present work, valence stabilization of Uranium ions in acidic solutions in presence of different classes of organic compounds has been studied. The results showed that in case of U(IV), methanol or formic acid are capable of providing about 80% protection while ethanol or acetaldehyde can provide about 70% protection. Propanol has the least protective effect i.e. about 54%. On using U(VI) instead of U(IV) in the irradiated solutions, the uranium ions were reduced and the formed U(IV) was protected as follows: formic acid or methanol can provide 69% or 63% protection respectively while ethanol, acetaldehyde or propanol can provide 50%, 35% and 24% respectively. In any case, protection exists as long as the organic additives were not completely consumed.