Abstract
In order to clarify the fragmentation mechanism of a metallic alloy (U-Pu-Zr) fuel on liquid phase formed by metallurgical reactions (liquefaction temperature=650℃), which is important in evaluating the sequence of core disruptive accidents in metallic fuel fast reactors, a series of basic experiments was carried out using molten aluminum (m.p.=660℃) and sodium under the thermal condition that the boiling of sodium does not occur. The thermal fragmentation of a molten aluminum drop with a solid crust is caused by transient pressurization within the drop confined by the crust even in such a thermal condition. This indicates the possibility that the metallic alloy fuel on liquid phase formed by metallurgical reactions can be fragmented without occurring the boiling of sodium on the surface of the melt.
