Message: "Cannot reflect particle 8136 off surface in a lower universe."

User Support
1

Hi all

I have the following problem: I try to model a fuel assembly which consists of 42 axial intervals (because I want different temperatures in each interval).
So I define the xy-arrays composed of the fuel pins and then I place them in the final z-array.
In each xy-array I have used 2 z-planes as transmission boundaries. Only for the first ant the last I used 2 vacuum boundaries. In the final z-array I use 4 reflective boundary conditions, in x and y direction.

When I run the problem I take some messages like:
“Cannot reflect particle 8136 off surface in a lower universe.”

“Could not locate particle 542 after crossing a lattice boundary”

I simplified the problem used only 2,3,4 axial regions. Then, the messages are significantly less, but they increase by increasing the number of neutrons per batch.
I think that the problem has to do with the boundary conditions, but I am not sure.

Could you help me?

Best regards,
Antonis

2

Hi Antonis,

Can you attach your input files in a zip folder. I will take a look at your model. I actually did the exact same thing recently with about the same number of intervals.

-Bryan

3

Hi Bryan,

Finally there was a mistake in a dimension. Probably this caused the problem. I think that the problem has been solved. If I detect anything, I will inform you.

Thank you.

Best regards,
Antonis

Τη Τρίτη, 18 Φεβρουαρίου 2014 8:21:43 μ.μ. UTC+2, ο χρήστης Bryan Herman έγραψε: