Full VHTR core mesh and geometry models can be created using RGG tools.
The mesh model has 21M hexes, it takes 96mins (serial run) and 3.5GB of RAM to generate the all assemblies and core mesh from scratch.
For this mesh model axial mesh interval (Z-direction) of 2 is used. The geometry model has ~33,000 volumes.
Isometric view of full VHTR core geometry (left), zoomed cross-sectional view of the top surface (center), further zoomed view of assemblies (right).
1/6th VHTR core geometry (left), closeup view of mesh (center), 1/12th VHTR core geometry (right).