Characterization of jet breakup mechanisms observed from simulant experiments of molten fuel penetrating coolant

At the beginning of FY 1991, the major components of the experiment apparatus had been constructed and transported to Argonne National Laboratory (ANL). The fluids to be used as fuel and coolant simulants had also been tentatively selected. Experimentation began in FY 1991, with eight experiments being completed as of 4/22/91. In each each experiment, a single jet of molten Wood's metal (a Bi-Pb-Sn-Cd alloy, melting point 70 1/2 C) was poured into a pool of room-temperature Freon-11 at atmospheric pressure. The interaction was photographed using high speed motion picture cameras. Eight additional experiments are planned for the remainder of FY 1991. X-ray still or motion picture photography will be used in several. As a result of the work completed during the first seven months of FY 1991, data showing the variation of the jet breakup length with its initial velocity and diameter have been obtained. These data allow an evaluation of the applicability of breakup length correlations in the literature to jet penetration of a volatile liquid with high vapor generation. They also indicate the locations at which an X-ray beam should be placed to best photograph the breakup of the jet within the opaque melt/coolant/vapor mixture. A brief scaling analysis is given. It provides the rationale for the current test matrix. Following this is a description of the status of the experiment apparatus and procedures. Then a brief discussion of completed and planned experiments is given. Finally, the implications of the test results are discussed