Theoretical and experimental analysis of the bistable convection loop for liquid-metal-cooled reactor emergency core cooling

In this paper, an emergency core cooling system incorporating a bistable convection loop (BCL) for current passive liquid-metal-cooled reactors is proposed. The system has two stable operating modes. During the off mode, the system is in a pure conduction mode and transfers very little heat. In the on mode, the system switches to the low-resistance configuration of a closed natural convection loop and transfers significant amounts of heat. The switching occurs passively because of changes in the reactor temperature. Theoretical and experimental analysis shows that a BCL designed to remove 7% of peak reactor power in the on mode loses only 0.0007% in the off mode, yielding a ratio of 10,000:1