Leakage flow characteristics of graphite seal mechanism with triangular cross-section for HTGR core support blocks

The prevention of coolant leakage flows is important for a thermal hydraulic design of a prismatic HTGR core. In particular, a seal mechanism for the core support blocks is necessary because gaps, which exist between core support blocks, induce leakage flows in the core. In this paper, a seal mechanism, which consists of graphite seal element with triangular cross-section and V-shaped seal seat, has been proposed. It is shown by the air flow experiments that the present seal mechanism is highly effective in preventing the leakage flows compared with the plate-type seal mechanism. It is also found that the pressure loss coefficient factor for this seal mechanism can be predicted by the effective end-gap area of the seal element. (author)