부산대학교 도서관

When a nuclear reactor with rectangular fuel assemblies runs for a long time, impurities and debris maybe taken into coolant channels, which may cause flow blockage, and the blocked fuel assemblies mightbe destroyed. Therefore, the purpose of this study is to perform a thermal-hydraulic analysis of a rectangular fuel assembly by STAR-CCMþ, under the condition of one subchannel with 80% blockage ratio. Arectangular fuel assembly of the International Atomic Energy Agency (IAEA) 10 MW material test reactor(MTR) is chosen. In view of the gasket material taken into the coolant channel is close to the single side ofthe coolant channel, in the flow blockage accident of the Oak Ridge Research Reactor (ORRR), a newblockage category called single side blockage is attempted. The blockage positions include inlet, middleand outlet, and the blockage is set as a cuboid. It is found by simulations that the blockage redistributesthe mass flow rate, and large vortices appear locally. The peak temperature of the cladding is maximum,when the blockage is located at the single side of the coolant channel inlet, and no boiling occurs in allblockage cases. Moreover, as the height of the blockage increases, the damage caused by the blockageincreases slightly