Fig. 1. The equivalent geometry modeling method for a cylinder surface by replacing it with entities

Fig. 2. CSG-based hierarchical multinomial tree structure for inversion modeling method

Fig. 3. CAD model inversion process for Monte Carlo computational model

Fig. 4. 3D CAD-based visualization of a typical 1/4 PWR model

Fig. 5. CAD-based visualization of burnable poison assembly

Fig. 6. 3D CAD-based visualization of model Was126

Fig. 7. The CAD model for the MCNP repetition structures

Fig. 8. The CAD visualization for the NUREG/CR-6115 nuclear reactor model