Model Of U-tube Steam Generator Research Articles

Transient Simulations of CPR1000 Nuclear Power Plant Implementing Advanced Mechanical Shim Control System

A novel concept of implementing the advanced mechanical shim (MSHIM) control system on the improved Chinese Pressurized Water Reactor (CPR1000) is proposed. The reactor power control system of CPR1000 is redesigned to adopt the MSHIM control system while the other parameters and control systems remain unchanged. To investigate the control performance and safety margins of this reconfiguration, the CPR1000 Full-Scope Simulation Platform (CFSSP) is first developed in MATLAB/Simulink with relevant control systems and protection system considered. The CFSSP consists of the one-dimensional nodal core model, the nonequilibrium three-region pressurizer model, the lumped-parameters dynamic model of U-tube steam generator with movable boiling boundary, and the balance of plant model. Based on the CFSSP, operational transients of step and linear turbine load changes were simulated and analyzed. The simulation results agree well with physical laws and the control performance is satisfactory. All key parameters are kept within acceptable ranges with enough safety margins and thus the protection system is not triggered. Therefore, the CPR1000 nuclear power plant implementing the MSHIM control system can safely sustain the ±10% full-power (FP) step changes and ±5% FP/min linear changes of load transients. This study can serve as a reference for the MSHIM control system application to pressurized water reactors.

REDUCED ORDER MODEL OF U-TUBE STEAM GENERATOR AND APPLICATION OF FUZZY AND LQR IN ITS LEVEL CONTROL

The water level of the U-tube steam generator (UTSG) in a nuclear power unit, which is an important process parameter, must be maintained in a safe range whether the unit is working under fixed or variable conditions. In this paper, a higher order UTSG model derived from the state equations is reduced using Balanced Truncation technique. Two controllers using Fuzzy logic and LQR techniques have been designed for the reduced UTSG model to control its water level. Comparison of these two controllers has also been shown through the simulation results. Also, a comparative analysis of the reduced order model and a previously developed UTSG model is presented by simulating both UTSG models with Fuzzy Logic and LQR techniques and the results are compared.

Adaptive Backstepping-Based Composite Nonlinear Feedback Water Level Control for the Nuclear U-Tube Steam Generator

As an important process parameter of the U-tube steam generator (UTSG) in a nuclear power unit, the water level must be maintained in a safe range when the unit is working under fixed or variable conditions. Because the dynamic responses vary significantly when the load changes, traditional control methods cannot effectively maintain the UTSG water level, especially with a low load. In this brief, an adaptive backstepping-based composite nonlinear feedback control scheme is proposed. The adaptive backstepping approach is used to design the water level controller and the feedwater flow controller separately, forming a cascade control structure to overcome the load disturbance and feedwater flow fluctuation. Furthermore, the composite nonlinear feedback control action is integrated into the feedwater flow controller to accommodate the opening constraint of the feedwater valve. Case studies, based on a practical nuclear UTSG model, show the effectiveness of this control scheme.

The Modeling and Dynamic Simulation of U-Tube Steam Generator

For comprehensive research on the dynamics of U-tube natural circulation evaporator in plant, the modular and lumped parameters method is used to establish the mathematical model of U-tube steam generator. Steam generator is divided into three parts in the model: primary water side, U-tube metal side and secondary water side. Secondary water side includes five modules. Then, the dynamic simulation experiment can be made on the basis of the simulation model. The experiment results consistent with the actual data and the adaptability and rationality of the model are verified.

Fault Detection in Nuclear Systems Using Sliding Mode Observers

The use of sliding mode observers as a model-based method is proposed for robust fault detection and isolation in linear and nonlinear nuclear systems. A sliding mode output observer and a sliding mode state observer are designed and applied to a U-tube steam generator model, a coupled nonlinear reactor model, and a pressurizer model to detect additive and multiplicative faults in the presence of uncertainties and measurement noise. Numerical results for both steady-state and transient responses of the example systems are presented to illustrate the effectiveness of the proposed method.