COMPARISON OF PID AND FUZZY-PID CONTROL FOR NUCLEAR STEAM BOILER LEVEL CONTROL

This paper presents control of water level of the steam boiler of nuclear power plant by using PID and Fuzzy-PID controller. In nuclear power plants, boilers are used to convert water into steam in which the water level control of boiler is very important as to provide sufficient cooling to the nuclear reactor and prevent damage of turbine blades. In order to compensate difficulty to control the level of boiler we propose the design of tuning of PID controller by a fuzzy logic controller in the level control of the steam generator of a nuclear power plant

Improvement of the operation and safety of nuclear power plants

This study investigated the importance of heating processes within a nuclear power plant. The application of Fourier’s law of heat conduction enables determining temperature distributions within the nuclear fuel rods. In contrast, convective cooling occurs on the road surface. The coolant, cladding, and fuel temperature distributions through a reactor are determined. In addition to heat transfer in the reactor core, some power plants engage heat exchangers to produce steam that is fed to a turbine-generator to produce electricity. Thermal power plants reject condenser heat to the environment through mechanisms such as cooling towers as according to a consequence of the second law of thermodynamics. These investigations provide a possible modeling approach and load the following control strategies for problematic nuclear power plants to provide an assessment of the concept designs. A load frequency control strategy and average temperature control mechanism are studied to get load following nuclear power plants. This study reports on the development and analysis of some novel versions and approximations of the fractional-order (FO) point reactor kinetics model for a nuclear reactor with slab geometry. These models evolve from the FO point reactor kinetics model, which has been derived from the FO Neutron Telegraph Equation for the neutron transport considering the subdiffusive neutron transport. This study also proposes a water level control system for a nuclear steam generator (SG). The control system consists of a feedback controller and a feedforward controller. The feedback controller comprised in the first order, the feedforward controller is of second order, and parameters of the two controllers are linked with the parameters of plant model; thus scheduling is easily implemented in practice. A model was developed for the thermal analysis of closed feedwater heaters in which wet steam is extracted from the steam turbine (and piped into the heater). Application of this model is of relevance to nuclear power plant diagnostics where the fluid flowing through the steam turbine is wet steam

Dynamic modelling, simulation, and control design of a pressurized water-type nuclear power plant

This article presents an integrated non-linear dynamic model of a Pressurized Water-type Nuclear Reactor (PWR) and associated plant components for control design and evaluation purposes. The model uses the first-principles approach to represent various components of the plant. The model considers the dynamics of the reactor core, thermal hydraulics, piping and plenum, pressurizer, steam generator, condenser, and turbine-governor system, in addition to various actuators and sensors. The response of the proposed model is tested using perturbations in different input variables. Various control loops implementing low-level PI control strategies are designed and implemented in the model to simulate the closed-loop behaviour of the plant. These include control loops for reactor power, steam generator pressure, pressurizer pressure and level, and turbine speed. Linear quadratic Gaussian-based optimal control strategies are further developed and implemented. Unique contributions of the work include the set of plant sections that are considered, the implementation of carefully tuned control strategies, the completeness of the model equations, and the availability of parameter values so that the model is readily implementable and has the potential to become a benchmark for control design studies in PWR nuclear power plants

A Framework for the Evaluation of Distributed Control Systems in Industrial Control Applications

The research develops a test-bench and framework to evaluate distributed control systems (DCSs) against industrial control system requirements. A real-time hardware-in-the-loop (HIL) test-bench and framework has been used for the evaluation of a DeltaV M3 DCS from Emerson Process Management. The test-bench measures: process control behaviour including overshoot and settling time; and I/O throughput, latency, and jitter for analog, digital, Modbus serial and OPC over Ethernet. The DCS successfully controls a real-time Matlab simulation model of a Nuclear Power Plant (NPP) steam generator, with a maximum water-level overshoot of 4.20%. The evaluated DCS has I/O throughput between 1.06 and 5.05 Hz, and latencies between 72 and 310 ms. The OPC over Ethernet is the most deterministic I/O channel, but has the lowest throughput. The test-bench and framework enables the evaluation of new technology for use in NPP and many other industrial control applications

17. Issues for Nuclear Power Plants Steam Generators

Open Access Boo

Оптимізація прямих показників якості систем автоматичного керування продуктивністю парогенератора

The system of automatic control of the productivity of the PGV-1000 steam generator of the power unit of the nuclear power plant with the WWER-1000 reactor is considered. This control system includes a system for automatically controlling the water level in the steam generator. The error signal, which is fed to the input of the productivity controller, is generated by the signal of the specified speed of the drive turbine, as well as pulses from the thermal power sensor and from the water and vapor pressure sensors. Based on the model of the water level control system in the steam generator, mathematical models of performance control systems have been developed under various control laws. To formulate optimization tasks for performance management systems, vectors from variable parameters of performance controllers are formed, constraints on these parameters are imposed, constraints are created for the areas of system stability, direct indexes of system quality are introduced, and a vector objective function is created that takes into account all imposed restrictions and quality criteria. Computational experiments on optimizing the controllers of productivity control systems were performed on the basis of direct quality indexes of systems by modified methods of step adaptation and Nelder – Mead. Analysis of the results of optimization of performance control systems allows us to conclude that, in comparison with the minimization of integral quadratic estimates, the optimization of direct quality indexes has made it possible to substantially improve the speed of the systems. The greatest value of the control time takes place for the differential controller, and the smallest identical values – for the proportional-integral and proportional-integral-differential regulators. Theoretically, the expediency of using a more simple proportional-integral controller in the steam generator productivity control system is justified. Additional analysis of the state variables in the productivity control system and comparison of transients before and after optimization allows us to conclude that the maximum deviation of the water level in the steam generator has decreased and its oscillations have disappeared. Also, fluctuations in water flow disappeared, the maximum deviation and oscillation of the control error decreas ed substantially, the overshoot and oscillations of other state variables practically disappeared. Thus, the optimization of the quality indexes of the automatic control system of the steam generator’s productivity has made it possible to significantly improve the main processes in it.Розглянуто систему автоматичного управління продуктивністю парогенератора ПГВ-1000 енергоблоку атомної електричної станції з реактором ВВЕР-1000. Ця система управління включає систему автоматичного управління рівнем води в парогенераторі. Сигнал помилки, який надходить на вхід регулятора продуктивності, формується сигналом заданої частоти обертання приводної турбіни, а також імпульсами з датчика теплової потужності та з датчиків тиску води і пари. На підставі моделі системи управління рівнем води в парогенераторі розроблені математичні моделі систем управління продуктивністю при різних законах регулювання. Для постановки задач оптимізації систем управління продуктивністю сформовані вектори зі змінних параметрів регуляторів продуктивності, накладені обмеження на ці параметри, сформовані обмеження для областей стійкості систем, введені прямі показники якості систем і сформована векторна цільова функція, яка враховує всі введені обмеження і критерії якості. Проведено обчислювальні експерименти з оптимізації регуляторів систем управління продуктивністю на підставі прямих показників якості систем модифікованими методами адаптації кроку і Нелдера – Міда. Аналіз результатів оптимізації систем управління продуктивністю дозволяє зробити висновок, що в порівнянні з мінімізацією інтегральних квадратичних оцінок оптимізація прямих показників якості дозволила істотно підвищити швидкодію систем. Найбільше значення часу регулювання має місце для диференціального регулятора, а найменші однакові значення – для пропорційно-інтегрального і пропорційно-інтегрально-диференціального регуляторів. Теоретично обґрунтовано доцільність застосування в системі управління продуктивністю парогенератора більш простого пропорційно-інтегрального регулятора. Додатковий аналіз змінних стану в системі управління продуктивністю і порівняння перехідних процесів до і після оптимізації дозволяє зробити висновок, що зменшилося максимальне відхилення рівня води в парогенераторі та зникли його коливання. Також зникли коливання витрати води, істотно знизилися максимальне відхилення і коливання помилки управління, практично зникли перерегулювання і коливання інших змінних стану. Таким чином, оптимізація показників якості системи автоматичного управління продуктивністю парогенератора дозволила істотно поліпшити основні процеси, котрі в ній протікають

Underground nuclear power plant siting

This study is part of a larger evaluation of the problems associated with siting nuclear power plants in the next few decades. This evaluation is being undertaken by the Environmental Quality Laboratory of the California Institute of Technology in conjunction with The Aerospace Corporation and several other organizations. Current efforts are directed toward novel approaches to siting plants within the State of California. This report contains the results of efforts performed by The Aerospace Corporation to provide input information to the larger evaluation relative to underground siting of large central station nuclear power plants. Projections of electric power demand in California and the country as a whole suggest that a major increase in generating capacity will be required. The problem is complicated beyond that of a large but straightforward extension of capital investment by increased emphasis on environmental factors combined with the early stage of commercial application and regulation of nuclear power sources. Hydroelectric power generation is limited by the availability of suitable sites, and fossil fueled plants are constrained by the availability of high quality fuels and the adverse environmental and/or economic impact from the use of more plentiful fuels. A substantial increase in the number of nuclear power plants is now under way. This source of power is expected to provide the maj or portion of increased capacity. Other power sources such as geothermal and nuclear fusion are unlikely to satisfy the national needs due to technical problems and the lack of a comprehensive development program. There are several problems associated with meeting the projected power demand. Chief among these is the location of acceptable and economic plant sites. Indeed a sufficient number of sites may not be found unless changes occur in the procedures for selecting sites, the criteria for accepting sites, or the type of site required. Placement of a nuclear plant underground has been suggested as an alternative to present siting practices. It is postulated that the advantages of underground siting in some situations may more than compensate for added costs so that such facilities could be preferred even where surface sites are available. By virtue of greater safety, reduced surface area requirements, and improved aesthetics, underground sites might also be found where acceptable surface sites are not available. Four small European reactors have been constructed partially underground but plans for large size commercial plants have not progressed. Consequently, the features of underground power plant siting are not well understood. Gross physical features such as depth of burial, number and size of excavated galleries, equipment layout, and access or exit shafts/tunnels must be specified. Structural design features of the gallery liners, containment structure, foundations, and gallery interconnections must also be identified. Identification of the nuclear, electrical, and support equipment appropriate to underground operation is needed. Operational features must be defined for normal operations, refueling, and construction. Several magazine articles have been published addressing underground concepts. but adequate engineering data is not available to support an evaluation of the underground concept. There also remain several unresolved questions relative to the advantages of underground siting as well as the costs and other possible penalties associated with this novel approach to siting. These include the degree of increased safety through improved containment; the extent and value of isolation from falling objects, e. g. aircraft; the value of isolation from surface storms and tidal waves; the value of protection from vandalism or sabotage; the extent by which siting constraints are relieved through reduced population-distance requirements or aggravated by underground construction requirements; and the value to be placed upon the aesthetic differences of a less visible facility. The study described in this report has been directed toward some of these questions and uncertainties. Within the study an effort has been made to identify viable configurations and structural liners for typical light water reactor nuclear power plants. Three configurations are summarized in Section 3. A discussion of the underground gallery liner design and associated structural analyses is presented in Section 4. Also addressed in the study and discussed in Section 5 are some aspects of containment for underground plants. There it is suggested that the need for large separations between the plant and population centers may be significantly reduced, or perhaps eliminated. Section 6 contains a brief discussion of operational considerations for underground plants. The costs associated with excavation and lining of the underground galleries have been estimated in Section 7. These estimates include an assessment of variations implied by different seismic loading assumptions and differences in geologic media. It is shown that these costs are a small percentage of the total cost of comparable surface plants. Finally, the parameters characterizing an acceptable underground site are discussed in Section 8. Material is also included in the appendices pertaining to foreign underground plants, span limits of underground excavations, potential siting areas for underground plants in the State of California, pertinent data from the Underground Nuclear Test Program, and other supporting technical discussions

Liquid metal magnetohydrodynamics (LMMHD) technology transfer feasibility study. Volume 2: Appendixes

For abstract, see N74-13466