[openmc-users] Correct my mistake

Hi Bikash,

The problem is mostly in how you are specifying cont_reg and refl_reg. When you use the & operator, this indicates an intersection of two regions. However, in those two cells, you are taking the intersection of regions which do not overlap, so the resulting cell won’t actually appear anywhere. For example, in cont_reg, you have -below_plane which indicates z < -6.0 and +above_plane which indicates z > 6.0. No point in space will satisfy both of those conditions simultaneously. What you need to do is either break up the cell into multiple cells (for example, one at the bottom and one at the top) or you can use the logical OR operator, |, which would indicate that the region is composed of the union of the operands for the operator.

Best regards,
Paul