MCNP error zero lattice element hit

In summary, the speaker is encountering a "zero lattice element hit" when trying to run a hexagonal lattice in MCNP5. They are seeking help to solve this issue and are considering extending the lattice or filling the missing wedges with another material. They also mention having to limit the lattice to 7x7 and adjusting dimensions in the cluster surface. The expert also questions the presence of fractional pins in the fuel array.
  • #1
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TL;DR Summary
I have been encountering "zero lattice element hit" when I try to run it in MCNP5. The input file is provided below. The square lattice runs fine, but the hexagonal does not. Hope someone can help me here. Thank you.
I have been encountering "zero lattice element hit" when I try to run it in MCNP5. The input file is provided below. The square lattice runs fine, but the hexagonal does not. Hope someone can help me here. Thank you.
 

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  • #2
That was diverting. :biggrin:

You have a hexagonal lattice filling a cylinder.

You have a hexagonal lattice almost filling a cylinder. A "zero lattice" means that nothing has been provided in a part of the lattice that a particle has arrived at. The white wedges have nothing in them. You can either extend the lattice and fill with some more pins. Or you can fill those wedges with something else. Or you can set their importance to zero.

Probably what you want is to define a new universe and fill it with something. Void or zirc or water or whatever makes sense. Then fill past the pins a step in i and j with that new universe.

homeless.png
 
  • #3
thank you very much for your help...I thought the problem was more complicated than that :). My problem with the hexagonal lattice is that I have to limit it to a 7x7 lattice and try to put it in a "circular" cluster surface. Maybe, it would be easier to adjust the dimensions in the cluster surface (#s 69-72). Again, thank you for your help :)
 
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  • #4
Out of curiosity, I was wondering about those fractional pins. Do you really want them in there? I would have expected a fuel array to consist of complete pins. With the placement you have, you have 19 complete pins in a nice 3-pins-on-a-side hexagon, and then a bunch of partial pins. What's up with that?
 

Related to MCNP error zero lattice element hit

1. What does the error "zero lattice element hit" mean in MCNP?

The error "zero lattice element hit" in MCNP refers to a situation where the program is unable to find any lattice element in the specified location. This can occur due to incorrect input data or a mistake in defining the lattice geometry.

2. How can I troubleshoot the "zero lattice element hit" error in MCNP?

To troubleshoot the "zero lattice element hit" error in MCNP, you can check the input data and make sure that the lattice geometry is properly defined. You can also try running the simulation with a simpler geometry to see if the error persists.

3. Can the "zero lattice element hit" error be caused by a problem with the material cards?

Yes, the "zero lattice element hit" error in MCNP can sometimes be caused by a problem with the material cards. Make sure that the material properties are correctly defined and assigned to the lattice elements.

4. Are there any common mistakes that can lead to the "zero lattice element hit" error in MCNP?

Yes, there are a few common mistakes that can lead to the "zero lattice element hit" error in MCNP. These include incorrect input data, missing or incorrect lattice element definitions, and problems with the material cards.

5. Is there a way to prevent the "zero lattice element hit" error in MCNP?

To prevent the "zero lattice element hit" error in MCNP, make sure to carefully check and validate all input data before running the simulation. Also, double-check the lattice geometry and material cards to ensure they are correctly defined. Running a test simulation with a simpler geometry can also help identify any potential issues before running a full simulation.

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