Simulation of shockwave propagation characteristics in nuclear reactor cavity during external steam explosion using unified SPH

Steam explosions in nuclear reactors pose significant risks to reactor safety and containment integrity during severe accidents. This study addresses the challenges of accurately simulating shockwave propagation and structural impact in such events by establishing a unified Smoothed Particle Hydrodynamics (SPH) framework. The proposed SPH model was optimized using GPU parallelization and validated against experimental results from shock tube, underwater explosion and high-velocity impact tests, demonstrating its efficacy in capturing shockwave-structure interactions. The model was applied to simulate steam explosions in the APR1400 reactor cavity under various conditions, examining factors such as the equation of state (EOS) for water, structural materials and explosive forces. The study further found that the choice of EOS and structural material greatly influenced the peak pressure and the extent of damage, with the Mie-Grüneisen EOS producing higher peak pressures and reinforced concrete showing higher damage resistance. These findings suggest that the unified SPH approach provides a comprehensive and robust framework for assessing steam explosion risks, offering crucial insights for optimizing reactor design and safety measures against such events.