I’m trying to run the example of hexagonal lattice .But i couldn’t define mesh correctly.
the code shows following error ( WARNING: Fission source site(s) outside of entropy box ) while running in eigenvalue mode.
Is there any way to define mesh for hexagonal lattice??
N.B:it’s not any valuable code but i’m learning to define mesh for hexlattice.
-Thank you
Untitled.ipynb (26.6 KB)
HI Ishtiakh,
The warning that you are seeing actually has to do with the calculation of Shannon entropy, not the hexagonal lattice itself. Shannon entropy is used to diagnose whether the fission source distribution has converged and relies on a mesh being overlaid on the geometry which it counts fission source sites in. If the mesh doesn’t cover all fissionable regions, you can end up getting these warnings. In your case, the mesh extends from z=-100 to z=100, but in your model it appears the cells extend to infinity in the z direction (nothing is constrained by a ZPlane). A quick solution would be to add z planes at z=-100 and z=100 with reflective boundary conditions, which would be equivalent to the geometry you currently have.
Best regards,
Paul
Hi Paul,
Does that mean openmc considers infinite axial length in Z direction as 200 cm ?
If not then whats the length of infinite axial length in openmc?
Thanks in advance
Hi paul,
i defined two Z plane as suggested. but i’m facing problem for y plane . as instead of y axis ,OpenMC uses another axis that is rotated 30degree clockwise. thats why i’m having the same warning.can you plese suggest me what to do with this one?
-Thanks
No, if you don’t specify any bounding surface in the z direction (or any other direction), particles can travel in that direction arbitrarily far.
The x/y bounds for your entropy mesh are not quite big enough. I would change them to -5.5 and 5.5 and that should get rid of the warning messages you are seeing.