In this work, a simple mathematical model in the time domain for the primary circuit of a PWR is used to determine a dynamic level controller for the pressurizer water level, along with a dynamic controller for the pressurizer pressure. This model is accurate enough to capture the nonlinear, time-varying, and switching nature of the system. The proposed controllers may not use the direct measurements of the pressurizer pressure. In fact, they rely only on the pressurizer wall temperature measurements, and the dynamics of the controller reconstruct the pressurizer temperature, and hence its pressure. A further advantage of a dynamic controller is that it can attenuate the classical drawback due to the long response of temperature sensors, which may cause some troubles to pressure control. The designed controllers are implemented in Simulink, a general-purpose tool for modeling, analysis and simulation of multi-domain dynamic systems. They ensure a good performance when applied to the model used to derive them, also in the presence of unmodeled uncertainties and disturbances. Their switching nature, reflecting the switching nature of the pressurizer dynamics, ensures better transient behaviors. Hence, they represent an evolution and an improvement with respect to classical PID controllers, usually implemented in standard control actions. It can be used, indeed, as a simple decision support tool in case of pressure sensors failure. To better test their performance, a more accurate model of a PWR pressurizer has been considered. Moreover, a performance study of the control systems in the presence of faults and/or reference accidents in III Gen PWRs has been considered. The performance of the pressurizer water level and pressure controllers has been tested in the case of a classical transient, the turbine trip, which can be due to the faulty closure of the turbine stop valve. This work is part of a preliminary prototyping simulation environment to serve as a basis for the development of an engineering simulator able to improve training effectiveness, or to offer a real-time decision support system to plant operators.
|Publication status||Published - 2012|
|Event||8th International Topical Meeting on Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies 2012: Enabling the Future of Nuclear Energy, NPIC and HMIT 2012 - , United States|
Duration: 1 Jan 2012 → …
|Conference||8th International Topical Meeting on Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies 2012: Enabling the Future of Nuclear Energy, NPIC and HMIT 2012|
|Period||1/1/12 → …|
All Science Journal Classification (ASJC) codes
- Human-Computer Interaction
- Energy Engineering and Power Technology
- Nuclear Energy and Engineering
- Control and Systems Engineering
Cappelli, M., Sepielli, M., Castillo-Toledo, B., Di Gennaro, S., & Muellner, N. (2012). Pressurizer pressure control in pressurized water reactors: Performance study of the control systems in the presence of a turbine trip. Paper presented at 8th International Topical Meeting on Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies 2012: Enabling the Future of Nuclear Energy, NPIC and HMIT 2012, United States.