مجله علوم و فنون هسته ای
سال چهل و سوم شماره 4 (پیاپی 102، زمستان 1401)

The present study investigated the structural, mechanical, and nuclear properties of two types of polymeric and metallic composites containing boron carbide particles. The neutron transmission test obtained lower neutron transmission in BPAER reinforced with B4C nanoparticles compared to the microparticle-reinforced composite. The stress-strain diagrams obtained from the tensile test show the improvement of the mechanical properties of the epoxy resin composite reinforced with B4C nanoparticles compared to the microparticles. The neutron transmission test also indicates an improvement in the nuclear properties of the Al-B4C nanocomposite compared to the Al-B4C micro composite. On the other hand, the density of this nanocomposite shows an increase compared to the micro composite. Also, regardless of the size and amount of carbide particles added, the density of all composite samples was lower than that of aluminum. Also, the hardness of the composite increased with increasing the amount of reinforcing phase, which was more in the nanocomposite samples than in the micro composite samples.

Proton decay occurs through the emission of a proton from the nucleus, resulting in a decrease in the atomic number of the parent nucleus of a unit. This decay occurs mainly in proton-rich nuclei. The proton emission mechanism is based on the quantum tunneling phenomenon and is expressed in the nuclei by Wentzel-Kramers-Brillouin or WKB approximations. The potential considered here includes the Coulomb potential for deformed nuclei, the centrifugal potential, and the nuclear potential. The nuclear potential was approximated by the proximity potential. The probability of the penetration from the potential barrier and the WKB approximation was obtained based on the half-lives of the proton decay. The effect of temperature on the surface tension of the hot nucleus was studied and a proportional relationship was considered by comparing it with the surface tension of liquids.  By applying changes in the proximity potential, the logarithm of the proton-decay and temperature-dependent decay logarithms were calculated  indicating better agreement with the experimental data. Then, in order to obtain the better comparison, the root of the mean square deviation was calculated indicating a good agreement between the laboratory and computational data in both cases

In this paper, Quantum Phase Transition (QPT) for the Xenon (122-132Xe) isotopes chain in the frameworks of the IBM-1 and IBFM-1 is considered. In order to study the QPT in this chain, we have used the observables such as: binding energy, two neutron separation energy, Alpha decay energy, R4/2 and B(E2). The results show that transitional nuclei in the regions of  for even-even isotopes and  for even-odd isotopes are 130Xe and 127Xe respectively.

The behavior of fission gases such as xenon and krypton have a significant effect on the performance of nuclear fuels, their active life,  and the length of the reactor operating cycle. Two important phenomena, including the release of fission gases from the fuel rod matrix and the resulting swelling, are currently the main challenges points in studying the performance of nuclear fuels. In this regard; and in order to multiscale modelling of nuclear fuel a meso-scale fuel performance code has been developed to analyze Fission Gas Release (FGR) and swelling under steady state conditions. The obtained results are compared with experimental data for low burn up to a maximum of 6.5 MWd / tUO2, where good agreement is achieved. In fact, this code is a bridge between data from atomic-scale calculations and macroscopic scales in nuclear fuel performance codes. The developed code, has the capability to be utilized as a standalone code, or to be called as a subroutine in other nuclear fuel performance codes. It is noteworthy that the development of the code for high burnup as well as transient conditions is underway.

The decontamination of structures with radioactive substances is one of the most important areas of environmental chemistry. In this study, an intelligent polymeric coating containing a Br-PADAP detector was made to identify and remove the uranyl nitrate contaminant (UO2(NO3)2.6H2O). In this study, the effect of pH was investigated for the first time. Also, the parameters of different substrates, detector concentration, contaminant drying temperature, coating drying temperature, and mechanical properties of the contaminant adsorption were investigated. The results of an evaluation of FT-IR, TGA, and liquid scintillation tests well prove the presence of uranium ions in the coating. The polymer coating containing the EDTA and Br-PADAP detector becomes purple to brown by absorbing a contaminant solution containing uranium ions. Quantitative evaluation based on MATLAB software image processing methods also shows a color change. Decontamination factors (DFs) in this coating were shown to be above 97% at 2000 ppm, and higher than in previous studies. The polymer solution was obtained with optimal formulation and flexible film.

In order to enhance applicability of Tehran Research Reactor (TRR) for irradiation test of nuclear fuels and materials and considering TRR potential to provide required neutronic and thermal-hydraulic conditions for irradiation tests on domestic nuclear fuel samples, TRR fuel test loop is designed and fabricated. This test loop with 10 bar nominal pressure and 20m3/h nominal volumetric flow rate is designed to simulate thermal-hydraulic conditions of the reactor core in which, the fuels will be used.  In this research, safety assessment of the consequences of loss of flow accident in the fuel test loop due to primary pump breakdown is performed and the functions of safety systems to provide continuous cooling for the test fuel samples and also to mitigate any undesirable consequences of this accident are evaluated. In this regard, the probable scenarios are simulated using a RELAP5 model and the ability of the safety features of the loop to prevent any damage to the test fuel rods is evaluated. The results reveal that safety systems of test loop can provide safe condition during the accident in which the meat and clad temperatures of test fuels remain within the permissible limits.

In radiotherapy, ionizing radiation is used to damage cells. Monte Carlo simulations of radiation interactions with DNA give us good information about the type of damage and their repair process, which can be very useful in treating cancer and protecting against radiation. The ionizing radiation damage includes single- and double-strand breaks as well as base lesions (SSB, DSB, BL). The DNA damage can be repaired through some processes within the cell. DNA damage, especially of DSBs that are mis-repaired or unrepaired, can result in cell death. This process plays a crucial role in killing cancer cells and treating cancer. In this research, first, the dose was calculated in the cell nucleus with the MCNPX code. Then, the possibility of different damage types in DNA was investigated by simulating the physical and chemical processes of low and high-energy electrons with the Geant4-DNA code. Then with the help of the Matlab software and mathematical modeling, we investigated the repair of DSBs for the latter energies. The results show that at ranging energies of 100 to 300 eV, the number of breaks increases, and for higher energies, it decreases due to the electron range in the cell nucleus. The repair reaction rate is also calculated from the NHEJ presynaptic process for ranging energies 100 eV to 1 MeV. In the repair section, the repair time at low energies is longer than the higher energies due to more DSBs.

Bone metastases are one of the main consequences of some cancers, such as breast, lung and prostate cancers, which are accompanied by severe pain in the bone area. Gallium-68 radioisotope with a half-life of 68 minutes is one of the most suitable options in Positron emission tomography (PET) is used in nuclear medicine. In this study, one of the zoledronic acid derivatives was synthesized as a bone-seeking agent and then attached to the DOTA chelator. The DOTA-ZOL compound was finally used for 68Ga labeling. All synthesized products were identified by FT-IR, NMR and MASS spectroscopies. The radionuclide purity of gallium-68 was calibrated by HPGe detector and determined with a multi-channel analyzer (99.9%). The radiochemical purity of the generator wash solution was investigated by thin layer chromatography using two different solutions (100%). Labeling of the prepared complex with 68Ga was performed by DOTA chelator and the radiochemical purity of the final complex at the optimized conditions (pH=4, temperature 98ºC, reaction time: 30 min) was examined by thin layer chromatography technique and determined about 97%. The results of this study showed that 68Ga-DOTA-ZOL is a suitable diagnostic radiopharmaceutical for imaging bone metastases by PET method.

High energy photons (10-20 MeV) that originate form medical linear accelerator in Radiotherapy treatment room, produce neutron. The produced neutrons id absorbed with different materials in the accelerator, the environment and even patient body that produced radioactive materials. These radioactive materials may pose a risk of radiation exposure to the radiotherapists who go to the treatment room frequently between patients. This process may cause internal radiation exposure in addition to external radiation exposure.  In this research after the expose of 18 MV X-Ray by medical accelerator (Varian 2300C/D), the spectrum of accelerator head was collected by portable HPGe detector and 19 radioisotopes were recognized.

Introducing the effective potential between plasma particles is one of the common methods to study the behavior of particles in plasma. In this paper, it has been tried to define the effective potential for fully ionized hot dense plasma by using the dielectric response function method. In the dielectric response function method, it is first necessary to introduce an initial potential function, and an effective potential function is obtained with the help of its effect on plasma. The initial potential function used in this paper is the Hulthen potential function, which is used for the first time in these calculations. In the following, the effective potential on the interaction of plasma particles such as electron-ion, electron-electron and ion-ion interaction are compared with other results obtained from other theoretical studies for the same conditions of plasma parameters. The results show that this effective potential includes both the effects of hot dense plasma, i.e. collective effects at long distances and quantum effects at short distances, and represents a very good description of the behavior of particles in hot dense plasma media.

Target Normal Sheath Acceleration (TNSA) mechanism is one of the most common proton acceleration mechanisms in the experimental setup. In this work, the effect of field ionization on the proton acceleration performance in result of the interaction of high intensity laser pulses with different pulse lengths was studied using two-dimensional particle in cell (PIC) simulations. For this purpose, two solid (neutral) targets as well as fully ionized plasma target, made of aluminum layer with thickness of 0.5 μm, and paired with a thin layer of hydrogen with thickness of 50 nm are considered.  Simulation results showed that considering the constant pulse energy and a medium laser intensity (here a0 =10 for pulse width of 25 femtoseconds) the use of solid structure leads to an increase in the maximum energy of the protons by about 36%. In addition, the difference in proton cut-off energy between the solid target and the ideal plasma one decreases with increasing the laser pulse width.

This paper studies the bifurcation types and phase portrait properties of ion-acoustic traveling waves in a plasma comprising warm adiabatic ions and energetic electrons with a nonthermal distribution function. A dynamical system is first derived for the evolution of the low-frequency wave, and then the bifurcation response is determined on the fixed points-energetic electron concentration plane. Our numerical results show that the motion dynamics of traveling waves undergo a transcritical bifurcation for a given value of energetic electrons. Both solitary and nonlinear periodic waves coalesce and switch their stability at the critical electron density value. Moreover, for higher values of the fast electrons density, a saddle-node bifurcation occurs, which leads to the propagation of periodic waves in plasma. The existence domain of bifurcation and transition between nonlinear modes are also determined for different values of ion temperature and energetic electrons density.

Among the noble gases, Xenon isotopes are the most widely used. So far, no specific strategy has been published for separating all Xenon stable isotopes with the highest number of stable isotopes. In this research, a computational code, SQCAS, is prepared to determine the target isotope separation strategy in light or heavy current. The prepared code investigates the separation of the natural isotopes in proportion to the feed concentration by changing the parameters of the square cascade and modeling it at each step. All stable isotopes of natural xenon are separated using a square cascade in 32 steps for the certain feed (200kg). The proposed square cascade has 20 stages. In each stage, 10 centrifuges were used. Also, the separation factor for the unit mass difference in this research equals 1.2. Using this strategy, the enrichment of nine isotopes increases from 0.9393, 0.0009, 0.01917, 0.2644, 0.408, 0.2118, 0.2689, 0.1044, and 0.087 to 98.72%, 91.3%, 92.79%, 92.63%, 83.77%, 90.12%, 91.64%, 95.68%, and 99.04%, respectively. The results show that the highest recovery is related to the end isotopes, and the lowest recovery is related to Xe-135 isotope.

In this study, organic gas steam liquid extraction (OGS-LE) by using a particular homemade extraction cell was proposed to extract and determine cadmium in aqueous solutions. The variables of interest in the OGS-LE method in this research are extraction solvent volume, pH of the aqueous solution, the molar ratio of extractant agent, and heated chamber temperature, which were investigated. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) of this method were found to be 0.03 μg L−1 and 0.09 μg L−1 for Cd2+ ions. The linear concentration range was 0.1-1 μg L−1 , and the percent relative standard deviation (RSD %) was 3.7%.

Magnetic ionic liquids (MILs) have received increasing attention as solvent systems in various extraction techniques. The MILs are obtained by incorporating high-spin transition metals within the ionic liquids. In this study, a rapid and straightforward approach based on MILs as the extraction phase was developed to extract and separate uranium from water samples. The hydrophobic MILs trihexyltetradecylphosphonium tetrachloromanganate ([P6,6,6,14+]2[MnCl42−]) was prepared and employed as extraction solvent. The MILs were dispersed into the aqueous sample solution as fine droplets by ultrasonication, and then a rod magnet was used to collect the MIL microdroplets from the aqueous solution. The effect of different experimental parameters such as pH, the complexing agent, the concentration of salt, and sonication time on uranium extraction efficiency were studied and discussed. The practical applicability of the developed method was examined using natural water samples, and the recoveries for the spiked samples were greater than 95 %. The results indicated that the method could be successfully applied to extract and separate uranium from real water samples.

The Chapdoni-Posht-e-Badam complex is located in the Central Iranian structural zone and the northeast of Yazd province. This complex is one of the areas with high potential for thorium-rare earth elements mineralization in Central Iran. In this research, the network modeling method has been used to determine the type and potential of Th-REE mineralization in the study area. Different methods such as geochemistry, geophysics, remote sensing, field observations, and laboratory works have been used, and different criteria have been considered for scoring. After applying the mentioned methods, creating a database, and combining multiple layers, the mineralization model or possible deposit types have been determined. This research uses a network method to integrate different data layers and model them to produce a mineralization potential map. The results obtained for different types of mineralization models were combined in the form of final modeling, and a comprehensive map of mineralization potential was prepared. Finally, mineralization types related to granite, metasomatism, and metamorphism were determined for thorium and rare earth elements in the Chapdoni-Posht-e-Badam complex. The mineralization potential of thorium-rare earth elements in the center and south of the study area is more than in other places.

The use of nuclear techniques can be helpful in the selection and implementation of optimal agronomic practices as well as the provision of appropriate management strategies in soil and water conservation, achieving sustainable development goals. In this study, we investigated the effects of applying wheat and maize crop residue at five rates, including 0, 25, 50, 75, and 100 %, on the dynamics of soil particulate organic matter (POM) and its origin at depths of 0-10 and 10-20 cm under conventional tillage and no-tillage systems were aimed. For this purpose, the natural abundance of carbon-13 (δ13C) technique was used. The results showed that increasing residue rates in the conventional tillage system increased the amount of δ13C at two soil depths of 0-10 and 10-20 cm. In the no-tillage system, increasing residue rates led to an increase of δ13C only for the depth of 0-10 cm, and no significant differences were observed among residue treatments at a depth of 10-20 cm. In addition, the comparison of δ13C values ​​of soil and plant residues of wheat and corn confirmed that the main source of soil particulate organic matter originated from the wheat residue, indicating the more substantial effect of wheat residues on improving soil organic matter than maize.

This study investigates the distribution coefficient of strontium in a soil sample in the south of Tehran. In this research, the columnar method  was used to determine the distribution coefficient of strontium. Also, the effect of three factors, pH, strontium concentration, and soil height in the column was studied using the RSM method's experimental design. For this purpose, five different levels were considered for each parameter, and the experiments were designed and performed by MiniTab software. According to the results obtained in the predicted model, pH, column height, interaction between pH and column height, the interaction between pH and strontium concentration, and interaction between strontium concentration and column height are important. The square of the coefficients as well as the concentration of strontium, did not have much effect on the distribution coefficient. The most significant effect is due to the height of the column, which increases with increasing the height of the column. The rate of conformity of the predictive equation with the actual values ​​is 96.39%, which is an acceptable value.

Shewanella RCRI7 has the ability to reduce uranium under anaerobic conditions. Bacterial function of one- and ten-day cultured colonies in terms of uranium removal ability, morphological changes and viability in anaerobic solution containing uranium and nitrate has been investigated in this study. The results showed that one-day bacteria grew faster than ten-day bacteria at a concentration of 2 mM Uranium, while the uranium removal percentage of ten-day bacteria is higher than that of one-day bacteria, which are adsorbed by the bacterial masses through biosorption. Bioremediation of uranium in one-day cultured bacteria was confirmed by XRD analysis, spectrophotometry and morphological examination by light microscopy. 4-month and 9-month samples from one-day colony had 96% and 99% uranium removal, respectively, indicating the stability of soluble uranium removal over long periods of time. One-day and 4-month samples containing nitrate and uranium also confirmed the ability to remove uranium in the presence of nitrate at a concentration of 20 g /L, which shows the ability of this native bacterium to reduce the uranium in the presence of nitrate, introducing this as a suitable option for future studies.

This paper provides a techno-economic assessment of coupling VVER-1000 Power Plants and hybrid desalination processes, including MED-TVC and RO systems, with a total 100,000 m3/day freshwater capacity. DEEP and DE-TOP tools initially developed by IAEA for evaluating nuclear desalination projects are used here. To reduce the environmental effect of rejecting waste brine and increasing the efficiency of the RO system, in the proposed hybrid desalination system, the waste of MED-TVC is used as the feed water of the RO system. DE-TOP obtained the most efficient extraction steam point to supply MED-TVC system with 90MWth at the point with a pressure of 1.1 MPa and mass flux of 121 kg/s. An intermediate circuit is considered to ensure there will be no contamination into the produced water to comply with IAEA safety requirements. In this manner, the power plant's cogeneration efficiency reaches 33% to 34%. Furthermore, the financial results show freshwater's levelized cost is almost 1.06 $/m3.