Computational- and experimental-based analysis of the load capacity of dowel-brick structure of graphite component in TMSR

Abstract

To ensure the structural integrity of graphite reflector and the insertion of the control rod in the seismic event, a finite element analysis (FEA) of the whole graphite core in Thorium-based Molten Salt Reactor (TMSR) is urgently required. The stiffness of the dowel-brick structure is one of the most crucial parameters to verify the finite element model in whole core modelling. In this paper, ten non-failure and ten failure tests have been carried out to study the stiffness and load capacity of the dowel-brick structure and to investigate how the size of the dowel affects these parameters. In addition, two groups of FEA have been performed first, whose results are used to design the above tests. The numerical and experimental results indicate that the load capacity of dowel-brick structure is significantly affected by the height of the dowel and the direction load applied. The failure load in the direction perpendicular to the line connecting two dowels is obviously higher than that in the parallel direction. Meanwhile, due to most of cracks occurring in the lower brick, it is identified as the weakest one in the dowel-brick structure. Furthermore, when the dowel is short, the equivalent stiffness coefficients of the dowel-brick structure in directions parallel and perpendicular to the line connecting two dowels are approximately equal. However, the latter will be much higher than the former when the dowel is long enough. The stiffness coefficients of the structure in two directions increase slightly as the diameter of the dowel increasing. The experimental results have been used in the numerical analysis of the whole graphite core modeling in TMSR.