Experimental test results of multi-channel test rig of T1 test section, 4

The multi-channel test rig (T1-M) of the fuel stack test section in the helium engineering demonstration loop (HENDEL) is a large-scale experimental facility which simulates one fuel column of the HTTR core. A crossflow test was carried out using the T1-M. The objectives of this test are to investigate the thermal and hydraulic characteristics in the fuel stack under the conditions that produced the crossflow through a gap from the outside of the graphite blocks into twelve coolant channels: the crossflow was forcibly produced by a parallel gap situated between the third and fourth blocks from the top of those in the heated section mounted in the vertical direction. Crossflow rate were about a half of the total flow rate of helium gas in T1-M for heated flow. A decrease of the gap width raised the crossflow rates in outer channels (No.7∼12) and also reduced those in inner channels (No.1∼6). It was found that the crossflow affected flow redistributions in the channels and temperature distributions of the fuel rods. (author)