Dynamic Modeling of a Cogenerating Nuclear Gas Turbine Plant—Part II: Dynamic Behavior and Control

Abstract

Using the dynamic model of the cogenerating nuclear gas turbine plant developed in Part I of this article, the dynamic behavior of this plant is analyzed and a control structure is designed. First it is determined how several design choices affect the system dynamics. Then the requirements and options for a control system design are investigated. A number of possible control valve positions in the flowsheet are tested with transients in order to make an argued choice. The model is subsequently used to determine the optimal working conditions for different heat and power demands, these are used as set-points for the control system. Then the interaction between manipulated and controlled variables is mapped and based on this information a choice for coupling them in decentralized feedback control loops is made. This control structure is then tuned and tested. It can be concluded that both heat and power demand can be followed with acceptable performance over a wide range.

HTR-10GT Dual Bypass Valve Control Features and Decoupling Strategy for Power Regulation

“…Three power regulation methods were generally adopted in such closed Brayton cycle: reactivity control for reactor outlet temperature adjustment, inventory control for slow power regulation maintaining high cycle efficiency, and bypass valves control for rapid power regulation. In almost all existing designs of reactor coupled closed Brayton cycles, such as MPBR, MGR-GT, GTHTR-300C, GT-MHR, ACA-CIA, and PBMR, bypass valve was set but with different strategies [2][3][4][5][6][7]. MPBR and GT-MHR applied single bypass valve for system simplicity: the bypass valve from MPBR design diverts the helium flow from the heat source and the turbines [2] and that from GT-MHR design bypasses the reactor, the turbine, and the high-pressure side of the recuperator [3].…”

“…The potential coupling phenomenon between the loops was neglected, as only 10% step load variation was analyzed in his research. Besides these 2 positions, Kikstra and Verkooijen [6] proposed 2 another alternative positions: from the compressor outlet to its inlet and to the recuperator low-pressure side outlet. Based on the control features obtained, Relative Gain Array method and Dynamic Relative Gain analysis were applied for input-output pairing and the interaction between different control loops were paid attention; however, no countermeasure was mentioned in his research.…”

Estudio de un sistema de generación industrial de potencia para cero emisiones de CO2

“…Existe un método de control adicional que se usa en turbinas de gas de ciclo cerrado. En este tipo de ciclos se puede crear un sistema de almacenamiento de gas que permite regular el gasto másico disponible, variando la presión mínima del ciclo [56], [57]. De esta forma se puede alterar el comportamiento de la turbomaquinaria, permitiendo que esta opere en las mismas condiciones adimensionales pese a la variación en la potencia producida.…”