Tally current across assembly surfaces of a hexagonal core

User Support
1

Hi all,

I want to tally current on boundaries of all the assemblies of a 2D VVER core. What’ the easiest way to do this? I notice that there is no HexagonalMesh in OpenMC, so I cannot just use a mesh surface filter like what users usually do for a rectangular lattice.
Maybe DistribcellFilter plus 6 SurfaceFilter for one assembly? However, does it mean that I need to define 6 redundant surfaces in assembly cell that coincide with the hexgonal lattice boundary?

2

By the way, is there a simple example of CellInstanceFilter introduced in 0.12? I wonder whether DistribcellFilter or CellInstanceFilter is better here if there are different types of assemblies in the core

4

I’ve tried DistribCellFilter combined with SurfaceFilter. Unfortunately, all the tallies are zero :sob:. I don’t know if it is related to this issue.

Besides net current, I also want to tally out current from each assembly like scores filtered by “DistribCellFrom ”. Very appreciate if someone can show me an example!

5

A few things to note here:

  • It’s not possible currently to tally currents across the surfaces in a hexagonal lattice. As you pointed out, we would need some kind of hexagonal mesh capability in order to do this coupled with the existing MeshSurfaceFilter class.
  • I don’t think combining CellFilter, DistribCellFilter, or CellInstanceFilter with SurfaceFilter will work. All of the cell filters are normally used for volume-integrated tallies. You can use a CellFromFilter however in conjunction with SurfaceFilter, which allows you to obtain partial currents across a surface rather than the net current (the “cell from” implicitly indicates which direction the particle is going across the surface).
  • We don’t have a simple example of CellInstanceFilter yet. You can think of it as being like DistribCellFilter, but instead of giving you results for all instances of a cell, you can pick and choose which ones you want. The main problem right now is that it is not straightforward to figure out the “instance index” that is needed. We’re planning on improving our visualization tools to support this so that you can look at geometry and figure out which instance you want.