Development and validation of the MCCI module in the SAFARI integrated severe accident analysis code

Abstract

This study presents the development and validation of the MCCI (Molten Core-Concrete Interaction) analysis module within the SAFARI (Safety Analysis Code For Severe Accident Risk Identification) code, a regulatory severe accident analysis tool under development in South Korea. The SAFARI code is designed to support Severe Accident Management (SAM) actions. As part of this code, a dedicated module has been developed using a Python-based computational framework specifically designed to perform MCCI analysis. Since MCCI plays a critical role in determining the progression and consequences of ex-vessel severe accidents, it is essential for the regulatory code to include a module capable of accurately analyzing MCCI behavior under a wide range of severe accident scenarios. Under these development objectives, the MCCI module incorporates multi-physics models capable of simulating key phenomena associated with corium-concrete interactions. Validation of the MCCI module was performed using experimental data from selected experiments, specifically ACE-L2, SURC-2, and CCI-2, covering validation scenarios for MCCI geometry, concrete type, and cavity conditions. The simulation results showed good agreement with experimental trends, demonstrating the module's reliability. Additionally, comparative analysis with other existing codes confirmed that the module delivers comparable performance, supporting its applicability in regulatory safety evaluations.