Experimental investigation on the characteristics of melt jet breakup in water: The importance of surface tension and Rayleigh-Plateau instability.

Highlights • An experimental apparatus is set up to investigate melt jet breakup in water. • Drop-shaped leading edges are formed in the air before penetration into water. • Rayleigh-Plateau instability appears and even pinches jet column into segments. • Rayleigh-Plateau instability has the dominant effect on melt jet column breakup. Abstract In the present study, an experimental apparatus is set up to investigate the characteristics and mechanism of melt jet breakup in water in the premixing phase of fuel-coolant interaction during nuclear reactor severe accident. Wood's metal is used as the simulant material. The melt jet breakup experiments are conducted under different jet diameters, melt temperatures, water temperatures and penetration velocities. The breakup process is recorded by a high speed video camera. The characteristics of the breakup of the leading edge and the jet column are analyzed in detail. It is concluded that Rayleigh-Plateau instability has the dominant effect on the melt jet column breakup in water. [ABSTRACT FROM AUTHOR]