ICONE19-43900 PREDICTION OF BYPASS FLOWS IN HTR-PM BY THE FLOW NETWORK METHOD

Abstract

The high temperature gas-cooled reactor is moderated by many graphite bricks. Gaps between graphite reflectors are possible flow paths that some fraction of cold helium may directly enter the hot plenum without being heated, which is a kind of bypass flow. The ratio of the bypass flows to the total flow is a key factor related to the peak fuel temperature in the normal operation of the reactor. Gaps are widely distributed in three dimensional structures, thus building proper flow network is the practical means to describe all the main flow and bypass flow paths by assigning proper nodes and links of the flow network. Graphically illustrated in the Vpower simulator platform, a preliminary flow network was built for the main flow and bypass flow paths. As the resistance performances of all flow paths determined by empirical formulas or CFD tools, the flow network was solved to show the effects of total mass flow rate, outlet pressure as well as the gap size on the mass flow distributions.