Reliability evaluation of integrated detritiation system for fusion reactors based on DBDT approach

Integrated detritiation system (IDS) would play a key role in controlling the tritium release and atmosphere cleanup under accident scenarios in fusion reactors, and thus it is very significant to evaluate and ensure its reliability. Up to now, many conceptual designs for IDS have been developed worldwide, yet few are focused on its reliability studies. Due to complex redundant designs and functional dependence, this system has notable temporal failure behaviors that traditional static fault trees (SFT) are unavailable to capture and evaluate. In this contribution, motivated to understand the effect of temporal failure behaviors on reliability of IDS, dynamic fault trees (DFT) are first to be adopted to study its reliability through using dynamic binary decision tree (DBDT) approach. The results show the reliability indexes for IDS calculated by DFTs are one to two times lower than those obtained by traditional SFT, which means some overly conservative reliability requirements on IDS could be relaxed. The results also demonstrate that the DFT-based reliability evaluation method would be of great help for the fusion energy system’s optimization design in the future.