Abstract The safe operation of Pressurized Water Reactors (PWRs) is highly dependent on the Pressurizer (PRZ) system to stabilize the primary coolant pressure fluctuations during normal operation and maintain the pressure within specified boundaries. The behavior of the PRZ system is inherently non-linear and time-variant. Thus, it may not appropriate and precise enough to model it by the use of transfer functions or linear time-invariant state-space forms. As far as the authors know, the RELAP5 thermal-hydraulic code is one of the best platforms to represent a best-estimate (realistic) model for the PRZ system so far. Although the RELAP5 is capable of modeling the PRZ as a non-linear, time-variant, and dynamic system in an unknown model structure, it only uses classic controllers such as PID and Lead-Lag. According to the above issue, the RELAP5 code and MATLAB software are coupled together in this paper to use the capabilities of both the MATLAB software (the ability to implement advanced controllers) and the RELAP5 code (providing an accurate thermal-hydraulic model for the PRZ system). Conclusively, this coupling provides a new platform for designing and utilizing various intelligent and advanced controllers for the PRZ system. Moreover, this paper fully presents a switching supervisory control based on Fuzzy-PID controllers (as a model-free and intelligent controller) for the VVER-1000 PRZ system to adjust both its pressure and level outputs. In this work, the PRZ is modeled as a Multi-Input Multi-Output (MIMO) system with consideration of the interactions between outputs (pressure and level). Eventually, the designed control system is used for several case studies. The results show the high performance of the presented control system for the VVER-1000 PRZ system that can be applied for other PRZ systems.

中文翻译：

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一种基于模糊PID控制器的RELAP5与MATLAB耦合VVER-1000增压系统切换监控设计

摘要 压水反应堆（PWR）的安全运行高度依赖于稳压器（P​​RZ）系统来稳定正常运行期间的一次冷却剂压力波动并保持压力在规定范围内。PRZ 系统的行为本质上是非线性和时变的。因此，通过使用传递函数或线性时不变状态空间形式对其进行建模可能不够合适且不够精确。据作者所知，RELAP5 热工水力代码是迄今为止表示 PRZ 系统最佳估计（现实）模型的最佳平台之一。尽管 RELAP5 能够将 PRZ 建模为未知模型结构中的非线性、时变和动态系统，但它仅使用经典控制器，例如 PID 和 Lead-Lag。根据上述问题，本文将 RELAP5 代码和 MATLAB 软件结合在一起，以使用 MATLAB 软件（实现高级控制器的能力）和 RELAP5 代码（为 PRZ 系统提供准确的热工水力模型）的功能。总之，这种耦合提供了一个新的平台，可以为 PRZ 系统设计和使用各种智能和先进的控制器。此外，本文全面介绍了一种基于模糊 PID 控制器（作为无模型和智能控制器）的开关监控控制，用于 VVER-1000 PRZ 系统来调整其压力和水平输出。在这项工作中，PRZ 被建模为一个多输入多输出 (MIMO) 系统，并考虑了输出（压力和水平）之间的相互作用。最终，设计的控制系统用于几个案例研究。