Sharif Digital Repository

Nuclear power is a prominent alternative of fossil fuels that can effectively solve global warming, acid rains and other consequences of air pollutions, caused by combustion. Despite such obvious advantage, this highly compact form of energy suffers from a big problem corresponding to its nuclear waste. Graphene oxide (GO), a lamellar material with wide range of surface functional groups such as epoxy (C-O-C), hydroxyl, and carboxyl offers large surface area as well as high sorption capacity for the metallic cations. This thesis study presents a supercritical, and co-precipitation synthesis of magnetite- graphene oxide (M-GO) in which Fe3O4 nanoparticles are simultaneously formed, surface... 

Iodine isotopes are among the most significant medical radioisotopes with a wide range of applications in therapy and diagnosis. The I-131 isotope is usually synthesized by irradiation of natural tellurium in atomic reactors. But there is an alternative route in which this isotopes is produced along with two other significant medical radioisotopes (i.e. Mo-99, Xe-131) by neutronic irradiation of uranium in the reactors. To separate iodine isotopes especially in the extraction process of fission fragments, it is necessary to be selective adsorption of iodine on a selective adsorbent. One of the most selective adsorbent for this application is copper. The aim of this study is to compare the... 

Lithium has 9 isotopes which two isotopes are stable and remaining isotopes are unstable and have half-life. Lithium stable isotopes include 6Li and 7Li that their abundance is 7.53% and 92.47% respectively. Importance of lighter lithium isotope appears for its small cross section against thermal neutron and producing fusion reactors fuel in nuclear industries. Thermal neutron absorption cross section for 6Li and 7Li are 950 barn and 37 mbarn respectively. Interesting of these isotopes in nuclear industry is due to the large difference in the absorption cross section.6Li compounds implied for tritium producing in coat of nuclear fusion reactor with DT fuel. Following tritium is used in... 

Natural boron includes two stable isotopes 10B and 11B with 19.3 and 80.7 weight percent respectivley.10B isotope has a high thermal neutron absorption cross section. So isotope 10B material is suitable for making atomic reactor control rods. Other and even more important applications of 10B are in disclosing neutrons in order to measure neutron reactors fluxes and also are in nuclear physics laboratories and medical radiation. This isotope also is used in the pharmaceutical and the military industries. There are several methods for separating boron isotopes. Among the distillation methods, thermal diffusion of BF3, distillation of BF3, distillation of methyl borate, boric acid distillation... 

Resin In Pulp(RIP) is One of the most important processes for separation of uranium from ore while concentration of uranium in ore is low , based on adsorption of uranium that exist in the slurry on onion exchanger resins .uranium ore is dissolved in sulfuric acid and slurry that contain uranium is produced,then this slurry enter stirred reactors and adsorption process is performed.RIP are accepted universally and now adays countries such as canada,south africa and australia use this process when concentration of uranium in slurry after leaching process is 100-500 ppm.in iran also this process is performing in ardacan-saghand mine.Kinetic of adsorption process in stirred reactors has been... 

In this work, graphene oxide (GO) and Amino ethyl phosphonic acid (AEPA) functionalized graphene were synthesized using chemical method. In addition, reduced graphene was prepared by chemical and supercritical methods. Physical, chemical, morphological properties of as-synthesized materials were investigate using XRD, FTIR, RAMAN, UV, TEM, TGA, and BET. Thickness of monolayer GO which synthesized using Hummer’s method was evaluated 1 nm using AFM. FTIR and CHN results were affirmed the presence of AMPA onto graphene nanosheets. Adsorption properties of functionalized graphene for Th ions from aqueous solution was examined. Isotherm adsorption results demonstrated that maximum adsorption... 

Many concerns are directed toward heavy metal pollutions due to its environmental hazards, and many researchers have been working on elimination of heavy metals recently. The large volume of industrial wastewater and the probability of potable water resources pollutions, clarifies the importance of heavy metals removal from wastewater. Removing Uranium among all other heavy metals is of a great importance because of its radioactive and chemical toxication. This thesis topic is “Synthesis and Functionalization of Grapheme for Uranium Adsorption”. In order that, Graphene Oxide is fabricated from Graphite utilizing Hummers and Offman’s method firstly, and it is functionalized by two ligands... 

Green chemistry seeks to reduce or eliminate the use of hazardous substances in the chemical industry through the development of new products and processes .The replacement of harmful, widely used solvents and reagents is a key part of this approach. Supercritical fluid such as CO2 or water are good solvent for replaceement Exchange reactions involving the displacement of hydrogen bonded to carbon by deuterium are of interest in a broad variety of disciplines, such as the preparative chemistry of isotopically labeled materials, fundamental studies of carbonehydrogen bond activation processes, and studies of the nature of catalysts. The low cost of water and its environmental friendliness... 

One of the steps in the production of nuclear fuel pellets used in the core of a nuclear reactor is sintering. Sintering means the consolidation of a pressed powder sample into an integrated solid. This process can be done in different ways, such as traditional sintering, microwave, spark plasma, etc. In the process of fabrication of nuclear fuel pellets, after producing uranium dioxide in powder form and making corrections on the size distribution of powder grains, it would be nolded and then sintered. In this research, the temperature evolution of the green pellets introduced to microwave heating were investigated. In this report, a brief overview of the principles of microwave heating is... 

The aim of this study was to investigate the rate of increase in temperature of a phantom equivalent to body tissue by different groups of magnetic iron nanoparticles in the external magnetic field to kill cancer cells based on the hyperthermia method. To achieve this goal, three groups of dextran magnetic nanoparticles with different properties and reduced iron oxide-graphene oxide magnetic nanoparticles by M-rGO supercritical synthesis method were used. After XRD, FTIR, SEM, FESEM, VSM, TEM characterization tests, these materials were placed in a phantom made of agarose gel and with the same properties, in a magnetic field with fixed characteristics for all groups and during the process of... 

Lithium has two stable isotopes naturally including 6Li at 7.5% and 7Li at 92.5% relative abundance. In spite of the similarities of lithium isotopes in common chemical reactions, they have some completely distinctive behaviors in nuclear reactions. 6Li has considerable neutron cross section capturing in thermal neutron range about 945 barns while this feature for 7Li is insignificant about 0.037 barns. This difference makes them to play different roles in nuclear uses. 7LiOH is applied for pH adjustment of coolant in light water reactors. 6Li is not only used as a shielding material against thermal neutrons, but also is known as a source of tritium in the blanket of fusion reactors which... 

One of the most convenient methods for the synthesis of metal oxide nanoparticles, inorganic ceramic materials and catalysts is supercritical hydrothermal method. In its pure form or mixed metal oxide nanoparticles have potential applications are wide. An important aspect of functional metal oxides of uranium dioxide as the selective catalyst for the conversion of methane to methanol and chlorinated organic matter decomposition is used. The main issue that led to the definition of this project was that nanoparticles synthesized with supercritical hydrothermal conditions influenced by change in the temperature. Temperature also affects the particle size and the conversion efficiency. This... 

If nuclear radiation is not weakened and absorbed, it can cause serious damage to human devices or the environment. Dual-purpose dry casks are one of the sources of nuclear radiation production as a place to keep the spent fuel assemblies. One of the ways to protect against them is to use shield. One of the most common of them is composite shield. The composite used in this study has a polymer matrix. The matrix of the used polymer is epoxy resin. In this study, two separate composites have been made to attenuate neutron and gamma radiation. In this thesis, first, by using the MCNPX code, the necessary simulations for the design and construction of composite shields have been carried out.... 

Uptake characteristics of alginate microcapsules containing D2EHPA/TOPO for adsorption of uranium from industrial effluent were examined using batch, stirred and column method .stable alginate microcapsules in dried form was developed by immobilizing of D2EHPA/TOPO in porous matrix of calcium alginate. Characteristics of microcapsules were carrying out by destructive chemical analysis, BET, SEM and TG .the synthesized microcapsules showed a good column properties and high selectivity and reusability. In addition, isotherm adsorption of calcium alginate and microcapsules were fitted with frendlich's equation .the microcapsules also demonstrated that, the uptake percentage was constantly high... 

In this study, epoxy resin has been modified by nano-clay additives using direct mixing method and epoxy-clay nanocomposites were designed and produced with optimized percentage of clay content. By adding the powder of born carbide and lead oxide in nanocomposites new compounds are obtained. The results are used for protection against neutron and gamma rays, respectively. After preparation of epoxy-clay-born carbide and epoxy- clay-lead oxide nanocomposite the effects of irradiation and carbon fiber on mechanical and thermal properties of nanocomposites were examined. The Nanocomposites were exposed to Electron Beam Irradiation (EBI) in 100 and 500 kGy doses to investigate the effect of... 

Storage of the spent nuclear fuels is one of the topics of interest in recent years and many researches have been conducted in this field in order to design storage casks for spent nuclear fuels. In this study, thermal-hydraulic analysis of a dry storage cask for Bushehr Nuclear Power Plant spent nuclear fuels is carried out. Geometry of the analyzed cask is taken from a Russian transportation cask TK-13. Drawing of the geometry is achieved with SolidWorks and it’s meshing is completed in Gambit. 3 different cases were considered for cask’s geometry and design: cask without spacers inside, cask with spacers inside, and cask with spacers inside and fins on the outside surface of the cask.... 

Although much progress has been made in eliminating, conserving, and reducing migration and emissions of radioactive materials, the risk of radioactive material release into the environment is still one of the most important hazards in the use of nuclear energy. In this study, graphene compounds have been used as adsorbents for the removal of radioactive materials due to their high level, cost-effectiveness and simplicity of the synthesis process of various composites. In this regard, the removal of strontium and cobalt by graphene compounds has been investigated. Magnetite nanoparticles were anchored on the surface of graphene by sol-gel method and adsorption in batch mode was investigated.... 

Graphene is pure carbon in the form of a very thin, nearly transparent sheet, one atom thick. It is remarkably strong for its very low weight. Graphene is a novel particle that can improve adsorption properties. We use graphene for Iodine gas adsorption. Iodine-131 (usually in the chemical form of iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine, where it is kept for periods longer than this isotope's radiological half-life of eight days. For this reason, if people are expected to be exposed to a significant amount of environmental radioactive iodine (iodine-131 in fallout), they may be instructed... 

In this study graphene and graphene adsorbent for the Co2+ ion were created from sodium phenoxide and calcium phenoxide, respectively, using the chemical vapor deposition method, and their chemical, physical, and morphological properties were investigated using FT-IR, UV, XRD, Raman, TEM, FE-SEM, and XPS. The results suggest that the optimum reaction condition for synthesizing mono-layer and multi-layer graphene is the 750 °C temperature for 30 min. The Co2+ adsorbing properties of the synthesized graphene adsorbent from calcium phenoxide was investigated. The investigation of solvation properties suggests insolubility above 650 °C and the kinetic data suggest the rapidness of the Co2+... 

The main purpose of this research is to select a suitable solution for regeneration of ion exchange resins of TR system of Bushehr nuclear power plant and also to compare and evaluate the possibility of using industrial cationic resin (Amberlite IR120) instead of nuclear grade cationic resin (Amberlite IRN97).First, different solutions for regeneration of cationic resins were investigated. For this purpose, three strong acids including hydrochloric acid (HCl), sulfuric acid (H2SO4) and nitric acid (HNO3) were selected and each of these acids was tested in two different concentrations and two different linear velocities; Also, to evaluate the appropriate solution for anionic resin...