NuDE: Development Environment for Safety-Critical Software of Nuclear Power Plant

Safety-critical systems are systems where it is essential that system operation is always safe [1]. Therefore, rigorous quality demonstration is important when developing software in safety-critical system. Generally, safety-critical software demands extremely high-confidence verification and validation (V&V) techniques. Additionally, software V&V should be performed in parallel with software development. In IEEE standard 1012 for Software V&V [2], V&V tasks are defined for each development phase. Software in Nuclear Power Plant (NPP) such as a Reactor Protection System (RPS) is also safety-critical software. RPS makes decisions for emergent reactor shutdown. Therefore, RPS software should be verified strictly and throughout entire development life-cycle. However, it is hard to apply these process and techniques, because the techniques are difficult to understand, the tools often work only in isolation, and the output is difficult to extract meaningful information. In order to overcome these difficulties, we developed a formal methods based process [3]. We also developed tools for supporting formal methods based techniques. In this paper, we introduce NPP’s safety-critical software Development Environment (NuDE), through the Integrated Environment (IE) approach.