Reliability analysis and safety model checking of Safety-Critical and control Systems: A case study of NPP control system

Abstract Non-functional requirements (NFR) play a crucial role in designing safety–critical and control systems. The failure of such systems leads to substantial financial loss, threats to human life, and adverse impact on the environment. Therefore, we develop a framework using a state-space model to quantify reliability in the design phase of the development life cycle to minimize the losses due to the system's failure after installation. State-space modeling is a powerful technique to develop such a system for behavioral and structural analysis. Since, a safety–critical and control system may comprises with hardware, software, and sometimes human aspects involved to operate it. Therefore, when we model such complex system using Petri Net then 'the state explosion problem arises. So, to get rid of this problem, we use an algorithmic-based reduction approach to reduce the states of the modeled system and optimize the state-space model. Further, we verify the safety properties of the system during the design phase of the development life cycle that gives confidence to the clients for the use of the system. In this work, a digital feedwater control system of a nuclear power plant (NPP) is taken as control system to illustrate our methodology.