Experimental study on JET instability and breakup behavior in liquid-liquid system

Mitigative measures against a core disruptive accident are important from the viewpoints of safety of a sodium-cooled fast reactor. In order to estimate the quench behavior of molten jets, it is important to understand how the jet breaks up in the coolant. The purpose of the present study is to clarify the jet instability and breakup behavior in immiscible liquid-liquid systems. In the liquid-gas system, jet breakup regimes can be categorized on the map described by the Ohnesorge and Reynolds numbers. Such a map for the liquid-liquid system is, however, not so much reported. In order to understand the jet instability and breakup in a liquid-liquid system, we conducted experiments using some combinations of immiscible liquids. We mapped the observed regime of jet breakup against the Ohnesorge number and the Reynolds number, and established boundaries between different jet instability regimes on the map. Finally, based on the obtained map, we discussed the jet breakup in the actual SFR condition from the hydrodynamic viewpoints. (author)