Experimental study of core emergency cooling

Investigation of non-stationary heat transfer is the basic method for transient and accidental regime studies of power installations. With better understanding of heat-transfer phenomena the evaluation of the equipment thermal safety becomes feasible which is the most important task for nuclear power installations. The report represents experimental data obtained from the study of a single- and seven-rods mock-ups of a fuel rod bundle. As a heater stainless steel tubes were used with 9 mm outer diameter,2500 mm heated length, 1 mm and 0.5 mm wall thickness. Degassed water or water saturated with nitrogen or carbon dioxide was applied as flooding medium. Experimental dependencies has been obtained for the rewetting front velocity versus the initial conditions as well as for the heattransfer coefficient and heat flux at the fuel rod imitator surface versus thermal head, mass flow rate and vapor content. The results of the vilual observations of the process are also given