CORRELATION FOR DOWNWARD MELT PENETRATION INTO A MISCIBLE LOW-DENSITY SUBSTRATE.

Downward penetration of a sacrificial bed material or a concrete basement structure by an overlying layer of core melt resulting from a hypothetical core disruptive accident is described as a major issue in postaccident heat removal studies. Questions concerning the occurrence of flow transition and its effect on melt penetration are reviewed. Thus far, no melting rate correlation applicable over the entire range of density differences envisioned in hypothetical situations was established. To promote understanding of the phenomena and to strengthen the data base of melt penetration, simulation experiments were conducted using various kinds of salt solutions (KI, NaCl, CaCl//2, and MgCl//2 solutions) as the working fluid and an air-bubble-free ice slab as the solid substrate.