Sensitivity Analysis of Unsteady Corium Solidification in an Initially Emptied Horizontal Turbulent Pipe Flow

Abstract

In a reactor core meltdown under postulated severe accidents, the molten material called corium could be ejected or relocated through existing vessel penetrations. There exists, however, a potential for plugging of melt flow due to its complete solidification providing the availability of an adequate heat sink. Simulations of the melt flow in a horizontal tube were carried out to conduct a sensitivity study on the effect of key parameters on the melt penetration distance and bulk temperature distribution of the corium. The Reynolds number was varied from 10,000 to 20,000, inlet temperature was varied from 2600 K to 3000 K, the corium thermal conductivity was varied from 10 W/m·K to 20 W/m·K, and the pipe diameter was varied from 0.0095 m to 0.019 m. In addition, a comparison was made with an analytical model based on a modified Epstein's model and a previous numerical model. The study provided insight into the lower bound, which was found to be 98 mm, and the upper bound was 258 mm when predicting the potential penetration length of corium in horizontal pipes.