(An) experimental investigation of the high pressure melt ejection from two different scaled reactor cavities

Abstract

High Pressure Melt Ejection (HPME) is one of the most important phenomena relevant to Direct Containment Heating (DCH) which could lead to an early containment failure during a severe accident of PWRs. The present work is an experimental investigation to measure the extent of the debris dispersal into the containment due to HPME. This experiments have been performed on 1/25-th and 1/41-st linear scale models of YGN 1 \& 2 reactor cavity. Water and Wood`` metal have been used as molten corium simulant, and also Nitrogen and Carbon dioxide gas have been used to simulate the discharge of steam and gas mixture from the breach of the reactor pressure vessel. In the present work, water test runs have been performed 276 times with 1/25-th and 1/41-st scale models and wood``s metal test runs have been performed only 35 times with 1/25-st scale model. The relation between the retained fraction in the cavity and the experimental initial conditions have been investigated. In spite of different scale models, the results shows that debris dispersal from the cavity begins at about the same pressure for a given driver gas and given liquid simulant and hole diameter. Also, using some of the dimensionless variables, the experimental correlation has been obtained. This correlation represents all the data within $\pm 6.5\%$.