The multi-channel test rig (T₁-M) of the fuel stack test section in a 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 objective of this test is 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 forcibily 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.
The crossflow was 43-56% of the total flow rate of helium gas in T₁-M for heated flow and 5-37% for isothermal flow, and that became more in an outer channel of Nos. 7-12 channels than in an inner channel of Nos. 1-6 with decreasing the gap width. Also it was found that the crossflow affected a redistribution of flow rate flowing into the ch nnels and a temperature distribution of the fuel rod.