الفهرس 
Energy EconomicsOnly 14 pages are availabe for public view
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Abstract
In this thesis, advanced control strategies for controlling the output power of NPS and water level of nuclear U-Tube steam generator are presented. Two major problems are considered in this research. The first problem that we considered is that the base of NPS model is a set of ordinary differential equations (ODE) known as the point reactor kinetics equations (PRKE). These equations which expresses the time dependence of the neutron population and the decay of the delayed neutron precursors within a reactor are first order and linear, and essentially describe the change in neutron population within the reactor due to a change in reactivity. One of the important properties in a nuclear reactor is the reactivity, due to the fact that it is directly related to the control of NPS. For safety analysis and transient behavior of the NPS, the neutron population and the delayed neutron precursor concentration are important parameters to be studied. An important property of the KE is the effect on output power of NPS. The PRKE has been solved and simulated using MATLAB environment, then six models of NPS is developed, the performance operation of NPS are investigated in two phases; the first one investigate the output power of NPS with assuming there is no external disturbance (reactivity is constant), the second phase of our investigation is the evaluation and analysis of NPS performance with existing of external disturbance (positive and negative insertion of reactivity) with assuming the power level of NPS is fixed at 100% power level. The main criteria for evaluation and investigation of developed model of NPS are the performance index measurement (PIM) for error such as; integral square error, integral absolute of error, integral time absolute of error and integral time square error. Statistical analysis is carried out. Since the comparison among ISE, IAE, ITAE and ITSE with variations of different proposed controller and DNG of NPS were done. Different proposed controller such as conventional controller (PID) and advanced controller like FC, OFC, and PSO. from simulation results we found that the cumulative hazard and fitting curve of ISE, IAE, ITAE, and ITSE with 95% confidence bounds for NPS when it’s subjected to external disturbance, also we observe that that cumulative data with fitting curve for each performance index measurements lies inside the confidence bounds (CB) at six DNG and starts to goes out of CB with decreasing the number of delayed neutron group of NPS. Therefore we conclude that the output power of NPS is highly affected with decreasing the number of DNG especially in transient region, and its starts to improve with increasing the number of DNG, this improvement becomes faster with applying advanced controller on the power control system of NPS. Moreover the solution and representation of PKE using MATLAB is easy and accurate compared with analytical and numerical solutions. The second major problem we considered in this thesis was the design of robust and effective ness of water level controllers for SG in NPS. The WL control problem of UTSG has been a main cause of unexpected shutdowns of NPS which must be considered for plant safety and availability. The difficulties in designing an effective level controller for UTSG arise mainly from; the dynamics of a nuclear SG is very different according to the power levels and changes as time goes on, Non-minimum phase characteristics of SG dynamics due to the so-called “swell and shrink” effect. An effective water-level controller to adjust the water level for UTSG in all power levels especially at low powers is developed. Linear quadratic regulator was applied to water level control of UTSG when there is no effect of feed water flow rate for the inlet of UTSG. Three element controls strategy were used in order to completely monitor the performance of UTSG when the water level, feed water flow rate and steam flow rate are changes. Advanced controller are developed such as fuzzy controller, optimized fuzzy controller with GA, optimized PID controller in case of taking into our consideration a huge effect of feedwater flow rate at different time of UTSG response on the performance of NPS. The simulation are carried out at 5%, 15%, 30%, 50% and 100% of nominal power of NPS, also the developed controllers were investigated at different desired water level (mm) and different values of steam flow rate (kg/sec). Simulation results shows that the effectiveness and robust of designed controllers on WL of SG, consequently improvement in performance operation of NPS. Moreover, the effect of feedwater disturbance on WL of UTSG has been reduced in all power ranges of NPS, and recovering time of water level of SG due to steam flow rate disturbance is minimized that will prevent unexpected shutdown of NPS and increases its availability with electrical grid. Also The comparison between conventional and the advanced controller showed a significant improvement in water set point tracking and an increased ability in disturbance (in the form of steam flow rate changes) rejection. Furthermore, the proposed control strategy exhibits a good robustness behavior. The computer simulations demonstrated the effectiveness of the controller in diverse operating conditions. This thesis is organized as follows: Chapter one is the introduction, the research background and motivations, methodology and contributions. Chapter two presents the introductory to nuclear power station, energy economics and security, functional principles of reactor neutronics kinetics, review of nuclear reactors, components of NPS and reactor control systems NPS model with the reactor kinetics equation, approximate solutions of the point kinetics equations, and the chapter concentrate on the nonlinear model of nuclear SG in NPS includes Mass balances equations; Energy balances equations, Experimental model of UTSG, and Verification of the WL behavior for SG. Chapter four focuses on research and design of different control strategies in WL of UTSG, and gives; verification of WL “Swell and Shrink” behavior for SG, two element and three element feedwater control of UTSG, conventional and advanced controller design for water level of SG and output power of NPS. Chapter Five present simulation results of DWL in case of without and existing steam flow rate disturbance with implementation of three element control strategy. Chapter six is divided into two sections; the first section presents the performance of NPS at different DNG without external disturbance, section two present the performances of NPS at different DNG in case of existing of external reactivity, error analysis in output power is evaluated with conventional and advanced controller. Chapter seven presents the conclusions and future work.