[Following are my chat with Paul]
Hi Paul,
In order to save the computational resource, we can simulate 1/8 reactor core if it is the symmetric unit. The symmetry planes are set to reflective Boundary condition when using MCNP to run simulation. However, there is no much explanations about the functions of the reflective boundary type in the OpenMC documentation. So I’m wondering if the symmetry planes can also be set to the reflective boundary condition to simulate a 1/8 core when we use OpenMC to run simulation ？If it is true, then what’s the difference between “reflective boundary type” and “rotationally-periodic reflective boundary type”.
Best regards！
Hi Benjamin,
Yes, any surface can be set to be reflective including a general plane surface on the diagonal for a 1/8 reactor model. A rotationally-periodic boundary condition is applied to a pair of x-plane and y-plane – it means that when a particle crosses the x-plane, it comes out on the y-plane, and vice-versa. That way, if you have rotational symmetry (but not reflective symmetry), you can still reduce the size of your model. That would normally be applied to 1/4 core models.
Copying the OpenMC user’s group mailing list on this email in case others have this same question in the future.
Best regards,
Paul