Comparison of Jet Explosion Experiment with Simulation Using the MC3D Code

Steam explosion, as a critical risk factor in severe nuclear accidents, involves a complex mechanism and is associated with significant uncertainties in current numerical simulation tools. The prevailing mainstream simulation programs have not comprehensively validated the simplified models of Fuel-Coolant Interaction (FCI), and the experimental benchmarking remains insufficient. This study based on the molten tin - water vapor explosion experiment conducted on the VULCAN test facility, this study performs a full-process simulation of both the pre-mixing and explosion phases using the MC3D V3.8 code. By comparing key parameters such as jet front position, pressure impulse curve, and energy conversion rate, the reliability of the MC3D code in simulating hydraulic fragmentation of molten materials and pressure wave propagation is assessed. The results indicate that the simulated jet dynamics during the pre-mixing phase align with experimental observations by approximately 90%. In the explosion phase, the pressure peak and oscillation period are well captured; however, the simulated pressure half-width is broader than observed, resulting in a relatively higher predicted energy conversion rate.