Modeling DCS of Nuclear Power Plant With Extended GO-FLOW Methodology

Abstract

GO-FLOW model is a success-oriented system modeling method which describes how the system configures its resources to achieve required functions by using basic functional units in terms of substances and demand flows in the system. The GO-FLOW models, which are directly built according to system structure drawings, can be used to analyze the reliability of a system with time and phased mission problems. With the development of Digital Control System (DCS), the reliability analysis of whole DCS has become an important task. However, there are some shortcomings using the traditional GO-FLOW methodology to model DCS: 1. There are not abundant operators in the GO-FLOW model to describe the control logic in DCS; 2. It is hard to model the relationship between the control actions and hardware devices using traditional GO-FLOW methodology; This paper presents an extended GO-FLOW modeling method. In this study, the GO-FLOW model is supplemented and improved, which can accurately describe the relationship and control logic between the hardware and control action (or human control action) in the running process of the DCS. In this paper, taking the Chemical and Volume Control System (CVCS) as an example, using the extended GO-FLOW modeling method established the model of CVCS, and the model of DCS control logic. This improved modeling method can be applied to the reliability modeling and evaluation of DCS.