Optical visualization and pressure measurement of pressure wave propagation in vapor explosion induced by a single molten metal droplet

Ueda, Hayate*; Asahara, Makoto*; Kitagawa, Kazutaka*; Miyasaka, Takeshi*; Kamiya, Tomohiro 

A vapor explosion is a unique explosive phenomenon that occurs due to the rapid interaction between molten material and coolant. It is a concern during severe accidents in nuclear reactors and can also contribute to the escalation of damage during submarine volcanic eruptions. The strong pressure waves generated in the initial stages are believed to propagate while affecting the surrounding molten material; however, their propagation characteristics are not yet fully understood. In this study, experiments were conducted in which a single molten metal droplet was dropped into water, and the pressure waves generated by spontaneous vapor explosion were measured using pressure sensors and a high-speed camera.