Sharif Digital Repository

One of the methods to enhance the economic performance and safety factor of nuclear power plants is to determine a suitable fuel loading strategy in a reactor core. Different methods have been already elaborated to choose the proper fuel loading pattern. Selection of the best pattern for fuel loading ensures the best use of fissile material and more safety during reactor operation. Perturbation theory method is one the methods which could be used to solve this kind of problems. The effect of non-uniform perturbations on the reactor operation can be evaluated by multigroup calculations and using proper space dependent group constants. In this study, a C# based program is developed to find the... 

In order to identify the representative radioactive waste streams at Bushehr Nuclear Power Plant (BNPP) for use in Scaling Factor Determination Program for BNPP, all the relevant technical documents of BNPP including the Final Safety Assessment Report (FSAR) and Operation Manuals (OM) were carefully studied. In addition, the waste stream lines were closely examined by frequently visiting the plant and consulting with the responsible technical staff of BNPP.
As a result, twelve distinct waste streams (2 streams of concentrated waste, 3 streams of sludge, 1 stream of spent resin of TC31B001 tank, 1 stream of spent resin of UZ20B001 tank, 1 stream of selective sorbent TR41B001, 1 stream of... 

Operational wastes of nuclear power plants are classified according to their radioactivity level & physical state. According to the radioactivity level, operational wastes are divided into low level waste (LLW) & intermediate wastes (ILW); & based on physical state they are divided into 3 groups of wet solid & liquid wastes, dry solid wastes & gaseous wastes.Bushehr nuclear power plants produce 1600 barrels of waste per year, among which dry solid waste is about 40 percent. According to the physical nature & treatment methods used, the dry solid waste is further classified into combustible, non- combustible, compressible & incompressible wastes.The purposes of dry solid waste treatment is... 

In order to ensure the safety of the plants, a set of commissioning tests based on international standards for nuclear power plants is carried out before operation. In this research, one of the Bushehr power plant commissioning tests, the loop connection primary circuit cooling pump test, was simulated using the RELAP5 code. In this test, the effects of loop connection primary circuit pumps on the thermohydraulic parameters and the eneterance of test-related systems was evaluated. After simulating the systems related to the test and extracting the results of the stable state, were evaluated the transient results was obtained with the experimental results of the test of loop connection the... 

In this study the modeling of Bushehr power plant containment is considered. In Bushehr atomic power plant, which has a unique design, the containment is similar to PWR power plants with a metal sphere, but the installed reactor is a VVER-1000. After a full study on the containment and its systems, the required date for modeling is gathered and afterwards, the engineering handbook is prepared for MELCOR input code and then the modeling and size classification of the containment is done in 4 different ways, including the control volumes of 1, 9, 23 and 30 and then the temperature, pressure and density of hydrogen is examined. The result of studying control volume sensitivity reveals that 23... 

Continuous variation of electrical loads in the power grid results in fluctuations of voltage frequency and. Accordingly, the need to the dynamic stability of the power grid would necessitates a constant balance between the production and consumption rates of electric power. In the same vein, given the launch of Bushehr nuclear power plant and its connection to the national electricity network, an investigation of the power plant’s capabilities in changing the produced power seems to be an important necessity.
Therefore, modeling the Bushehr reactor core in the DynCo code, the present thesis is aimed at investigating the reactor behavior during the power change periods with the... 

The most important task of a power system is generating and transmitting electricity for consumers, according to electricity quality standards. One of these quality criteria is preservation of grid frequency close to nominal value with continuity of energy delivery to consumers. Electricity is a specific commodity that its generation and consumption should be equal continually; otherwise the network frequency will change and may become unstable, causing severe damage to the network equipment. There for different control and protective actions are deployed to maintain balance between generation and consumption, and thus to keep grid frequency close to nominal value. Characteristics of... 

Neutron fluctuations in both low and high power reactors provide important information about the system. The origins of these fluctuations are different in both regimes. In low power the branching process is the reason of these fluctuations. But the random nature of technological processes such as boiling in the reactors cooling and mechanical structure vibrating such as control rod and fuel rod created the neutron noise. Mathematical descriptions and applications of neutron noise for each mode are different. In common mode, fluctuations in the neutron detection system, determine some parameters and determin the start abnormality in system. In this study the spatial dependence of the cross... 

In this study the modeling of low pressure injection system to remove heat from the reactor core of Bushehr nuclear power plant(BNPP) after it has been paid off. After a full assessment of the primary circuit and the Bushehr nuclear power plant emergency cooling system, all the information needed to model the primary circuit and the low pressure injection system and the plant were collected in the available evidence. Then, according to the code, a code RELAP5 standards for light-water reactors(LWR) in steady state and transient parameters termohydraulic is a component of the hydrodynamic and thermal structures suitable for modeling of low-pressure injection system and primary circuit... 

Due to inherent dangerous on human and environment safety in the nuclear power plant has significant importance. In order to ensure the safety of the plant and proper functioning ofits various components,before its operational exploitation, a series of commissioning tests should be conducted according to international standards for nuclear power plants. In addition, safety of the plant can be guaranteed bymodeling of transient states and possible scenarios of accident in different situations.In this research,by gathering geometric data and information about the facilities installed in the plant, modeling of Commissioning test of Bushehr Nuclear Power Plant (BNPP) and its associated accident... 

One of the ways to enhance the safety and economic performance of nuclear power plants, is to choose an appropriate policy for arrange the reactor fuel assembly in the beginning of each cycle. There are variety of ways to optimize the layout of the fuel in the reactor core, but to achieve more than one goal, choosing multi-objective method can be used.One of the intelligent optimization methods is the genetic algorithms that emulate nature of biological processes and can be used to optimize two or more of the target.The goals of this research is to increase the neutron multiplication factor is to make maximum use of the fuel in the reactor and maintain the radial power peaking factor for... 

Due to nuclear power plants’ growing roll in providing energy, analyzing probable accidents and their prevention is of vital importance. The thermal-hydraulic shock accident which happened in Bushehr nuclear power plant deaerator has been simulated in this study. Steam bubble collapsing which takes place in two phase medium by mixing steam and subcooled water leads to this kind of shock causing financial and physical irreparable damage in nuclear power plants. For carrying out this simulation, first an steady state model of the deaerator was run using RELAP5 code and then using this model and other plant’s data such as the ropert of the accident and plant’s Final Safety Analysis Report... 

Ion exchange resins are widely used in nuclear industries. These spent resins result in the production of a large amount of low and intermediate level radioactive wastes, therefore, the treatment and immobilization of spent ion exchange resins are the major problems in the development of nuclear power plants.In this research, in a laboratory scale, we tried to find the suitable procedure and formulation to immobilize a specific group of cation-exchange resins which is used in Bushehr nuclear power plant (AMBERLITE IRN-97H) in the cement matrix. The solidification matrix consists of five constituents: anti sulfate slag type portland cement, cation-exchange resins, diatomite, sodium hydroxide... 

Spent fuel assemblies are kept in spent fuel maintenance pools, designed at the vicinity of the reactor, after consuming. As capacity of these pools are limited, fuel assemblies should be transported to outside of the reactor building for maintenance. Transportation cask is used for this reason which is Russian type, named TUK-13, at Bushehr Nuclear Power Plant. The aim of this project is to ensure proper removal of heat from the transportation cask(TUK-13). For this purpose, numerical computational fluid dynamics method is used. The software used in this study is the Comsol. The temperature range suitable for any part of the chamber is different; but the most sensitive and the most... 

The safety and optimal performance of nuclear reactors require online monitoring in the core. One of the most important requirements of core monitoring is the knowledge at all time of the neutron flux distribution in the core. The present M.Sc thesis describes a method which avoids the solution of time dependent neutron diffusion equation and uses online readings of the fixed in-core neutron detectors to reconstruct the three-dimensional (3D) neutron flux distribution. The essential idea of nodal synthesis method is separation of time and space dependence of the neutron flux distribution. The time dependent section of the flux distribution is determined by neutron detector readings and space... 

The raw and conditioned operational waste streams of Bushehr Nuclear Power Plant (BNPP) was determined by reviewing numerous plant’s documents (such as FSAR and operational documents) as well as by interviewing with persons in charge of BNPP waste management office. It was found that low/intermediate (type І and ІІ) level operational waste streams generated in BNPP is divided into eight independent streams. By using gamma emitting radionuclides as virtual DTM nuclides and determination of scaling factors for these nuclides, it was concluded that all the 8 waste streams can be grouped into one, that is, a universal scaling factor can be applied for all the 8 waste streams. In addition the... 

Given many computing errors in current systems, a method appears necessary for predicting the nuclear parameter quickly and accurately. In this thesis, a neural network was used to predict safety in a nuclear power plant in order to develop an operating aid tool for preventive measures.First, some studies were conducted on appropriate feature selection for training neural networks. Some case studies have also been carried out on parameter prediction through soft computing in a power plant. In the next section, an expert judgment was taken into account to select DNBR (Departure from Nucleate Boiling Ratio) as a criterion for safety evaluation in the exploitation of a nuclear power plant (PWR)... 

Inadvertent opening safety valve of pressurizer (SVP) is one of the most common initiator events in Booshehr nuclear reactors with occurrence frequency of 1.1E-0.2. This event has the third rank in initiator event among 16 other events (Loop and Compensated LOCA were ranked as first and second respectively). So special attention must be paid to SVP and the operators need to have specific trainings on this matter. In this thesis, the SVP as initiator event is being considered and the sequence which lead to core damage (CD), according to design informations is being modeled moreover the qualitative and quantitative analysis is carried out. In the modeling process we have used the SAPHIRE...