Three-loop Monte Carlo simulation approach to Multi-State Physics Modeling for system reliability assessment

Multi-State Physics Modeling (MSPM) provides a physics-based semi-Markov modeling framework for a more detailed reliability assessment. In this work, a three-loop Monte Carlo (MC) simulation scheme is proposed to operationalize the MSPM approach, quantifying and controlling the uncertainty affecting the system reliability model. The proposed MC simulation scheme involves three steps: (i) the identification of the system components that deserve MSPM, (ii) the quantification of the uncertainties in the MSPM component models and their propagation onto the system-level model, and (iii) the selection of the most suitable modeling alternative that balances the computational demand for the system model solution and the robustness of the system reliability estimates. A Reactor Protection System (RPS) of a Nuclear Power Plant (NPP) is considered as case study for numerical evaluation.