Integrated System Failure Analysis with Chemical Techniques (IS-FACT) for TRISO SiC Coating Safety

SUMMARY & CONCLUSIONSThis work integrates a reduced-order Arrhenius kinetics sub-model into the Integrated System Failure Analysis (ISFA) framework to form the Integrated System Failure Analysis with Chemical Techniques (IS-FACT) method. This method enables the diagnosis of system function states for chemically driven processes in the conceptual design phase. The chemical sub-model introduced in IS-FACT actively exchanges state variables with the physical system to capture coupled effects such as temperature, pressure, and species inventory changes.IS-FACT was applied to the silicon carbide coating stage of the tri-structural isotropic (TRISO) particle chemical vapor deposition process, modeled across 52 failure modes and a baseline nominal operation, with failure modes including leaks, clogs, insulation and heating faults, signal errors, and control faults. Each failure was simulated for 100 discrete steps to map failure mode propagation and determine the subsystem with the highest impact on system functionality.Across the 52 failure modes, IS-FACT shows that failures in the precursor-carrying pipelines have the highest influence on the system’s functional operation. IS-FACT is shown to successfully model internal physio-chemical component impacts through a range of physical failure modes. The results demonstrate that a chemical sub-model can improve diagnosability during systems’ early design stages, providing earlier and clearer function state classification under chemistry-driven failures.Future work will incorporate higher-fidelity chemical models with non-ideal reactor effects, such as advanced fluidized bed hydrodynamics and temperature flux, and extend IS-FACT to encompass the full TRISO coating process.