A method of formal requirement analysis for NPP I & C systems based on UML modeling with software cost reduction

Abstract

In this work, a formal requirement analysis method for Nuclear Power Plant (NPP) instrumentation and control (I&Q systems is suggested. This method uses unified modeling language (UML) for modeling a system visually and software cost reduction (SCR) for formally verifying the system. Since object-oriented methods enable us to analyze problems in terms of the objects in a real system, UML models are useful for understanding the problems and communicating with people involved in a project. In order to analyze problems more formally, SCR is used and the UML models are converted into SCR tabular notations. This work tries to acquire the flow-through from UML models to SCR specifications by suggesting additional syntactic extensions for UML notation and a converting procedure. The proposed method has been applied to a dynamic safety system (DSS) and inadequate core cooling monitoring system (ICCMS), which are parts of a NPP I&C system. Through these applications, some errors have been detected in the existing system requirements. Furthermore, in this work, through the comparison of our proposed method with the conventional inspection, we conclude that our method can complement the limitations of the inspection, which suffers from lack of detectability. (C) 2002 Elsevier Inc. All rights reserved.