ERROR: Maximum number of lost particles has been reached

User Support
1

Hello everyone,
I am trying to build a Pin_Cell, the openmc model was divided into many cells, which I defined as a series of concentric cylinders and some planes to cut them. In detail, the entire model was divided into 14 layers along the z-axis. For each layer, every single fuel pellet was quartered, and each of its four layers was divided into 4 cells, along with which the cladding as quartered and altogether the coolant was divided into 4 cells as is illustrated in attached figure.
plot_36

When I run the simulation, it breakdown with the ERROR:Maximum number of lost particles has been reached.AND Some Warnings.

ERROR20220301
ERROR20220301565Ă—529 56.2 KB

I use the default boundary style with my cutting planes.
How to solve the Error? Here I attached my case, so that I can get your help soon.

Best regards!
Zhuangli
geometry.xml (27.9 KB)
materials.xml (713 Bytes)
plots.xml (214 Bytes)
settings.xml (548 Bytes)
tallies.xml (1.5 KB)

2

Here’s an x-y slice plot of your model at z=12 (generated using the handy openmc-plotter tool):

image
image2046Ă—1580 242 KB

You can see that there is one area that is lacking a cell definition, so when particles reach that they don’t know where to go (hence all the errors you’re seeing about lost particles).

1 Like
3

Hi @paulromano i’m facing the same problem as it shows the following,“Maximum number of lost particles has been reached” how i can i find the problem for my model?the particle is always lost for the same surface number.this is what i got using plotter,

Screenshot from 2022-03-02 11-52-34
Screenshot from 2022-03-02 11-52-341920Ă—1080 112 KB

4

sorry i was wrong, there are many surfaces like this.

5

Thank you Paul! You helped me fix this error.
So nice are you! Now the simulation is running safely!
About openmc-plotter, I am sure I have installed it, when from a directory containing an OpenMC model run: openmc-plotter . The importERROR appear, I don’t know what that means.

D071:~/VScodeProjects/singleOnePin$ openmc-plotter
Traceback (most recent call last):
File “/home/lz/anaconda3/bin/openmc-plotter”, line 5, in
from openmc_plotter.main import main
File “/home/lz/anaconda3/lib/python3.8/site-packages/openmc_plotter/main.py”, line 8, in
from PySide2 import QtCore, QtGui
ImportError: /lib/x86_64-linux-gnu/libgssapi_krb5.so.2: undefined symbol: krb5_ser_context_init, version krb5_3_MIT

Best regards!
Zhuangli

6

Sorry to bother you, Paul.
About openmc-plotter, I have solved it by creating a new conda-env and use command:

conda install -c conda-forge pyside2

to install pyside2, and it works now.
Also see this post.

Best regards!
Zhuangli

7

Hello, I am currently facing this exact issue, could you tell me if you found a solution to this? I have checked the overlapping geometries and so far, I could not find the reason behind this problem.

Thanks in advance.

8

Hi mo,
Take it easy and then review to check your code of the model, Maybe the gap remain in your model, be carefully to check.

9

The geometries were defined twice and they were overlapping, I was able to solve the issue.

Thank you.

10

Hello everyone!
I’ve been stuck on the same geometry error for a week now. I can’t figure out which cell contains the surface that is causing the geometry problem in Jupyter notebook.
I have attached my Jupyter code.
I need some help.

Thanks in advance!
DEA_OpenMC.ipynb (129.6 KB)