HIGH-PRESSURE SIMULATION EXPERIMENT ON CORIUM DISPERSION IN DIRECT CONTAINMENT HEATING

Purdue 1/10 scale direct containment heating separate effects experime nts under a reactor vessel pressure up to 14.2 MPa are presented. With the test facility scaled to the Zion PWR geometry, these tests are ma inly focused on the cerium dispersion phenomenon in order to obtain a better understanding of the dominant driving mechanisms. Water and woo ds metal have been used separately to simulate the core melt, the reac tor vessel being pressurized with nitrogen gas analogous to the steam in the prototypic case. The entire test transient lasted for a few sec onds, and the liquid dispersion in the test cavity occurred within onl y 0.5 s. To synchronize the data acquisition and blowdown transient, t he test initiation was triggered by breaking two rupture discs in the liquid/gas delivery system. Parameters characterizing the liquid trans port were obtained via various instruments. Important information abou t the mean size and size distribution of the dispersed droplets in the test cavity, the liquid film flow transient, the subcompartment trapp ing, and the liquid carry-over to the containment has been obtained. T hese results, along with data from a previous low pressure (1.4 MPa) e xperiment carried out at Purdue University, form a solid database for further theoretical analysis.