| Abstract [eng] |
In this works study of thermal-hydraulic processes in nuclear reactor active zone using ANSYS software were made. Main goal of this work is to analyze thermal dynamics processes which occur in the reactors active zone. To achieve this goal following main task needs to be reached: 1.Analyze main parts of advanced boiling water reactor ABWR; 2.Analyze futures of ANSYS program package and capabilities of ANSYS FLUENT program package; 3.Conclude research model, create its geometry, mesh and define boundary conditions; 4.Perform calculations and analyze results; In the beginning of this works it is reviewed evolution of nuclear power plant with advanced boiling water reactor, main parameters, advantages and disadvantages i.e. analyzing principle flow diagram of nuclear power plant with advanced boiling water reactor, advantages of reactors containment and its evolution. For pressure vessel of ABWR reactor improvements were also made – most of the housing parts (nearly 1,000 tons weight) been minted from a single work piece and external circulation pump were refused to use. These two major improvements enabled for constructors significantly to increaser reactors safety levels and reduce probability of loss of coolant accidents (LOCA). There are also analyzed in more detail ABWR reactors design features - analyzed the reactor internal pumps, steam separator and steam dryer, the layout of the fuel assemblies in the reactor core and the architecture of fuel assemblies GE14. Not less attention is paid to review futures of the ANSYS software package and to conclude the research model. Model compiling includes three major parts – the creation of model geometry, computational mesh creation and the most important part - describing of boundary conditions. In the third chapter of this work “Futures of ANSYS programe package” is analyzed possibilities and specifics of main tool of this work – ANSYS FLUENT. ANSYS FLUENT is just a part of ANSYS program package family. ANSYS is also able to analyze electronic, structural changes, mullti phisics problems and systems issues. When literature is analyzed and tool is selected, the research model is concluding. As a research model four bundle fuel module (cell) was chosen. Because of large and complicated geometry few simplifications must be done: 1.Lifting handle, spacers, upper and lower tie plates were removed; 2.Central water rods were replaced by hollow rods; 3.Fuel rods are modeled as simple solid cylinders without holders and pins. When the research model is ready mesh was generated and boundary conditions were set. Key assumptions were that the nuclear reactor is stopped and only the residual heat is released for which drain is necessary to maintain sufficient coolant flow. After all calculations and results analysis were done, it was noticed that calculated flow rate is sufficient to maintain removal of residual heat form nuclear reactor. |
