Particle not located

User Support
1

Hi everyone,

I’m trying to simulate one third of a FHR fuel element (see image). In that image, in the red stripes there are triso particles, 210 along x-axis, 4 along y-axis and 1 along z-axis. The blue color denotes the coolant, the gray the wrapper structure (graphite), and the yellow the grpaphite planks that contain the fuel stripes. All the boundary conditions are reflective.

I defined the entire model but when the simulation starts, I am having many WARNINGS like this:

“After particle 40 crossed surface 27 it could not be located in any cell and it did not leak.”

And after those warnings, this ERROR:

“Maximum number of lost particles has been reached.”

Please, any idea on what could be happening?

Thank you in advance for your help.

Javier

ElementXY.jpg

2

Here a figure to show the complete fuel element (top view).

Javier

FHR_000.png
FHR_000.png1031×437 234 KB

3

Hi Javier,

I would suggest trying to run in geometry debugging mode, which will check for overlapping cells. This is the most common cause of lost particles. Running in geometry debug mode can be done with (from the command line):

openmc --geometry-debug

or (from the Python API):

openmc.run(geometry_debug=True)

Best,
Paul

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