Crushed model and uniaxial compression analysis of random packed ceramic pebble bed by DEM


H. Chen, Q. Xu, S. Wang




Fusion Engineering and Design



Ceramic pebble bed are applied in the solid blanket for the fusion reactor, the performance of pebble bed affects the tritium breeding of the solid blanket. Particles may be crushed while the blanket is working in the fusion reactor and thermo-mechanical properties of pebble bed will be changed. Studying the properties of pebble bed under the crushed scenario is important.A method using discrete element method (DEM) to study the mechanical behavior of the crushed pebble bed is proposed in the paper. It assumes that some crushed particles are randomly distributed in the pebble bed and that each crushed particle is replaced by a group of small particles. Based on the method, the 0%, 0.5%, 1%, 1.5% crushed models of the Li4SiO4 and Li2TiO3 pebble bed are established respectively, in which the percentages refer to the crushing ratio.Then, the uniaxial compression tests (UCTs) are simulated on the pebble bed with bed strain up to 1%. The results show that under the same bed strain, the bed stress decreases as the number of crushed particles increases.Compared with Li4SiO4 pebble bed, the Li2TiO3 pebble bed need larger pressure to reach the same bed strain. Besides, the effective elastic modulus of the pebble bed is also analyzed under the uniaxial compression tests.


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