Conventional probabilistic safety assessment (PSA) provides a systematic framework for risk evaluation based on event-tree methodologies. Recently, increasing attention has been given to dynamic analysis approaches that incorporate time-dependent system behavior and multi-phenomena interactions during accident progression. The Dynamic Integrated Consequence Evaluation (DICE) platform has been developed to support accident sequence analysis as part of PSA. Previous studies applied DICE to design-basis accident analysis through coupling with MARS-KS and to severe accident analysis through coupling with MELCOR.
In this study, an interface connecting DICE and the thermal-hydraulic system analysis program Flownex was designed and implemented to enhance the extensibility of DICE. Flownex supports component-based system modeling and integrated control logic representation and enables modeling of systems composed of multiple modules. Its capability to represent coupled power, thermal, and fluid systems also provides modeling flexibility for integrated energy systems and Power-to-X (P2X) analyses. A data exchange structure was developed using the Flownex API to transfer thermal-hydraulic calculation results and system state information between Flownex and DICE. In addition, a Python-based interface was implemented to improve the flexibility of coupling DICE with external analysis codes.
The developed DICE–Flownex system maintains the core structure of the original DICE platform while enabling the incorporation of system-level simulation results from Flownex into accident progression analysis. The capability of DICE–Flownex was demonstrated through dynamic accident sequence analysis of a loss-of-coolant accident (LOCA) scenario in a hypothetical SMR system.