ON THE SIMULATION OF TRANSIENTS AND ACCIDENTS IN PWRs WITH DIGITAL INSTRUMENTATION AND CONTROL USING AN LQR DIGITAL CONTROLLER

摘要

New nuclear power plant designs are including integrated I&C digital systems for protection, control, alarming and monitoring. Existing operating nuclear power plants, as is the case of Angra 1 nuclear power plant, have to consider the replacement of their I&C analog systems by digital systems for retrofitting their facilities. However, before replacing the analog control loops by digital ones it is necessary to design and evaluate their performance, which requires modeling of the plant and its control system with extensive simulations under several normal and abnormal operation conditions. This paper discusses the use of a linear quadratic regulator (LQR) digital controller for evaluating the plant stability behavior before the actuation of the reactor protection system. The objective is to evaluate the effect of digital controllers on plant behavior for several transients and accident conditions. For this purpose, a numerical model was developed and implemented as a Matlab tool. This paper discusses an adequate framework in order to simulate a set of transients and accidents that constitute the design basis in the final safety analysis report of PWR power plants to evaluate the performance of digital controllers such as LQR regulators.