MCNP lattice of the fuel assembly input file?

In summary, the input file does not use lattices and the pin diameters are slightly different. Changing the universe fill to universe 1 fixes the geometry errors.
  • #1
Islam Nabil
14
1
TL;DR Summary
There is an input file of a simple lattice 16 x 16 fuel assembly. I have a message blocking the run of the code; bad trouble in subroutine newcel of mcrun source particle no 1 random number 6647299061401 zero lattice element hit. what is the wrong?
There is an input file for a simple 16 x 16 lattice fuel assembly. I have a message blocking the run of the code;
"bad trouble in subroutine newcel of mcrun source particle no 1 random number 6647299061401 zero lattice element hit."
What is wrong?
 

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  • latice k code 16 16 no center cylinder.Txt
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Last edited:
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  • #2
There is an error somewhere in the geometry definition. If you change the filename of the input file to add .txt you can attach it to a post we can have a look at it.

If you can't share the input file you could try to debug it by plotting the geometry, but our help becomes very indirect.
 
  • #3
Alex A said:
There is an error somewhere in the geometry definition. If you change the filename of the input file to add .txt you can attach it to a post we can have a look at it.

If you can't share the input file you could try to debug it by plotting the geometry, but our help becomes very indirect.
Upload the txt file ...
 

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  • Laaty.Txt
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  • #4
Yes, if you click the button 'Attach files' you can find the file, if the name ends .txt
 
  • #5
Alex A said:
Yes, if you click the button 'Attach files' you can find the file, if the name ends .txt
Already uploaded
 
  • #6
Alex A said:
Yes, if you click the button 'Attach files' you can find the file, if the name ends .txt
Name changed
 
  • #7
Sorry, maybe I needed to refresh the page or maybe I did not look at the first post!

Your lattice has universe 0 fills. I have not seen that before. You are cutting that out of the rpp being filled. Ok.

I did mcnp ip inp=file
Clicked to enter a command into the plot window and did,
pz 0
To see a cross section through the middle. Most fuel element positions are undefined. It will take me some time to look at this.
 
  • #8
Firstly your lattice is xz instead of xy.
fill=-8:9 -9:8 0:0
not
fill=-8:9 0:0 -9:8

Secondly the 0 universe fill is creating a space outside your (cooling?) tubes that is not defined. Changing the universe 0 entries to universe 1 fixes that. That is the usual way to create a 'background' cell, refer the lattice universe to itself. I don't see any other problems at the moment. The geometry errors seem to have gone and the input file now runs a kcode.
 

Attachments

  • latk2.txt
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  • #9
Alex A said:
Firstly your lattice is xz instead of xy.
fill=-8:9 -9:8 0:0
not
fill=-8:9 0:0 -9:8

Secondly the 0 universe fill is creating a space outside your (cooling?) tubes that is not defined. Changing the universe 0 entries to universe 1 fixes that. That is the usual way to create a 'background' cell, refer the lattice universe to itself. I don't see any other problems at the moment. The geometry errors seem to have gone and the input file now runs a kcode.
Thank you, thank you very much, Doctor... The problem has already been resolved... Thank you...
 
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  • #10
I'm not sure what your final objectives are, but this assembly is at room temperature.
I've attached an input for a 16x16 case that uses a fuel temperature of 900 K and all other
temperatures are set at 600 K.

Unfortunately, this doesn't use lattices and the pin diameters are slightly different from what you have.
 

Attachments

  • ce16-1.mcnp.txt
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  • ce16-1.png
    ce16-1.png
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Likes Islam Nabil and Alex A
  • #11
rpp said:
I'm not sure what your final objectives are, but this assembly is at room temperature.
I've attached an input for a 16x16 case that uses a fuel temperature of 900 K and all other
temperatures are set at 600 K.

Unfortunately, this doesn't use lattices and the pin diameters are slightly different from what you have.
Thanks a lot doctor... King regards
 

FAQ: MCNP lattice of the fuel assembly input file?

What is the purpose of defining a lattice in an MCNP input file for a fuel assembly?

The purpose of defining a lattice in an MCNP input file for a fuel assembly is to accurately model the repetitive geometric structure of the fuel rods within the assembly. This allows for efficient simulation of neutron transport and interaction within the reactor core, providing detailed insights into the behavior of the fuel assembly under various conditions.

How do I specify the geometry of a lattice in an MCNP input file?

The geometry of a lattice in an MCNP input file is specified using the "lattice" keyword, followed by parameters that define the type of lattice (e.g., hexagonal or rectangular), the dimensions of the unit cell, and the arrangement of the cells within the lattice. You will also need to specify the material and boundary conditions for each cell within the lattice.

What are common errors encountered when defining a lattice in MCNP, and how can they be resolved?

Common errors when defining a lattice in MCNP include incorrect cell definitions, mismatched boundaries, and improper material assignments. These can often be resolved by carefully checking the input file for syntax errors, ensuring that all cells are properly defined and bounded, and verifying that the correct materials are assigned to each cell. Using visual tools to inspect the geometry can also help identify and correct errors.

How can I model different materials within the same lattice in an MCNP input file?

To model different materials within the same lattice in an MCNP input file, you need to define separate cells for each material within the lattice structure. Each cell can be assigned a unique material number and corresponding material properties. The lattice definition will reference these cells, allowing you to create a heterogeneous lattice with various materials.

What is the significance of the "fill" card in an MCNP lattice definition?

The "fill" card in an MCNP lattice definition specifies the arrangement of cells within the lattice. It defines how the unit cells are populated with different materials or cell numbers. The "fill" card essentially maps the internal structure of the lattice, indicating which cells are placed at each position within the lattice grid, thus determining the overall composition and geometry of the fuel assembly.

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