Reliability Analysis of Core Protection Calculator System using Petri Net

As digital systems are introduced to nuclear power plants, issues related with reliability analyses of these digital systems are being raised. One of these issues is that static Fault Tree (FT) and Event Tree (ET) approach cannot properly account for dynamic interactions in the digital systems, such as multiple top events, logic loops and time delay. This study proposes an approach to analyzing the reliability of Core Protection Calculator System (CPCS) using Petri Net (PN) modeling. The PN, one of the dynamic methodologies, allows modeling event dependencies and interaction to represent the time sequence and delay time for dynamic events. This study applies the approach to the reliability analysis of CPCS. In order to analyze the digital system modeling, further studies are required with the dynamic modeling methods and the software in the digital system. Modeling of digital systems should be realistic to account for the system characteristics and be able to predict system behavior.