Analysis of a Passive Emergency Core Cooling System for Research Reactors

When a loss of normal forced flow occurs for research reactors with normal downward core flow, the downward flow must be kept for a sufficiently long time to prevent fuel damage during flow reversal from downward flow to upward flow. In usual, research reactors with thermal power lower than 10 MW can accomplish the initial core cooling safely with a downward inertial flow driven by a pump flywheel. After the flow reversal, natural circulation cools down the reactor core. However, the inertial flow is not sufficient for research reactors with thermal power higher than 10 MW. Therefore, the reactors usually have an emergency cooling pump to achieve an appropriate core cooling. This paper deals with a performance analysis of a passive emergency core cooling system for a research reactor with thermal power of 14 MW and normal downward core flow. The passive emergency core cooling system consists of a vertical tank and a pipe connecting the core outlet plenum and the tank