Hi guys,
I just finish an eigenvalue calculation of PWR reactor core with 8E5 particles per generation. But In the calculation process, there is some warning information such as:
“WARNING: Couldn’t find particle after reflecting from surface 28” or,
“WARNING: Could not locate particle 596598 after crossing a lattice boundary.”
I have no idea where does the warnings information come from, but it looks like do not affect the calculation process.
If anyone body knows this problem please contact me. I’ m worried about it will affect the accuracy of the calculation results.
Many thanks,
Yiming
Hi Yiming,
Occasionally particles are “lost” (that is, OpenMC is not able to figure out which cell the particle should be in) if a surface coincides with a lattice boundary, or if a surface in a geometry with nested universes coincides with a surface at a different level of the geometry. In this case, the particle history is terminated. There is a tolerance on how many particles are allowed to be lost before the simulation aborts. The tolerance is small enough (maximum of 1 in a million) that you don’t have to worry about these few particles altering the accuracy of the calculation. Nevertheless, we have made some fixes in the code since the last release that should prevent many of these lost particles.
Best regards,
Paul