Error running RectLattice with >10.000.000 elements

User Support
1

Hello,

I run into problems when trying to implement the reference female phantom from ICRP110 report. It is frequently used in the field of radiation protection and dosimetry.

The phantom is basically implemented as a RectLattice composed of 299x137x348 (=14.255.124) elements, each of these contains one of 142 universes (representing organs or tissues) but I cannot plot it or run simulations. I get an uninformative message ending as “RuntimeError: OpenMC aborted unexpectedly.”

Interestingly, I can successfully run and plot it if I decrease the number of elements in the lattice or if I set the same universe to all elements of the lattice.
For instance, only using 299x137x250 voxels (= 10.240.750) instead of the 14.255.124 original ones, I get this nice image:

image
image448×835 38.9 KB

Any idea why it doesn’t work and how to solve it? Would there be a limit on the number of elements or universes filling a rect lattice?

Thanks.

Best,

JD

2

Hi JD,

can you share your inputs (.xmls)?

I have some experience with phantoms and voxels in OpenMC.

Cheers,
Perry

3

@JDBE Sounds like you may be running out of memory. One thing you can try is turning off the creation of offset tables for material cells (unlikely to be needed in your case):

settings = openmc.Settings()
settings.material_cell_offsets = False
4

Thank you both for the quick feedback.

Turning off the creation of offset tables for material cells worked great. The simulations now run fine.

I also managed to plot the phantom, simply using:
root_plot = openmc.Plot()
...
openmc.plot_inline(root_plot)

I was using the plot function from the root_universe (root_universe.plot(...)), but the lattice cell was not directly filling the root_universe, it was nested deeper (if this description makes sense…). Maybe this was too much for my laptop memory.

Best,

JD