| Abstract: | In a high-temperature gas-cooled reactor core, which consists of prismatic graphite fuel elements, leakage flows of coolant gas occur through gaps between blocks. Since the effects of these leakage flows on the total flow distribution are significant, their flow features must be clarified. In this paper, the leakage flows (crossflow through the interface gap between contacting fuel elements and the permeation flow through the fuel elements) in the normally stacked fuel elements were studied. In the basic experiments, leakage flow rates were measured using small-scale graphite blocks to determine the equivalent interface gap width and the permeability. The experiments using the full-scale fuel element were also carried out and the results agreed well with those of the basic experiments. Furthermore, a simple flow model was devised to predict the leakage flow in the fuel element. |
