Coolability of layers of molten reactor material

Abstract

Chapter 15 is devoted to the coolability of layers of molten nuclear reactor material. Such physics is important for designing of stabilization of spread melt in reactor compartments. After defining the problem with its boundary conditions and some simplifying assumptions the system of differential equations describing the process is presented: mass and energy conservation. The following effects are taken into account: the molten steal dropped in the melt or originating inside the melt; the gas release from a sub-layer; the viscous layer; the crust formation; the buoyancy driven convection; the film boiling; the heat conduction through the structures; oxide crust formation on colder heat conducting structures. The existence of a metallic layer is also considered. Some test cases are presented to make easy the application of the presented models: oxide over metal and oxide besides metal. A simple model for gravitational flooding of hot solid horizontal surface by water leading to hyperbolic system is also presented.