Can MCNP solve the geometric coincidence issue with a semi-cylinder and cuboid?

In summary, the conversation discusses how to solve a geometric coincidence problem in MCNP, where shapes need to intersect and be defined in a specific way. The conversation also addresses a specific issue with cell definitions and the use of positive and negative surfaces. The issue is eventually resolved by correcting an error in the x-axis, but there is still a problem with cell card 1. There is also mention of a discrepancy between MCNP and VisEd in terms of displaying the model.
  • #1
chengmo
9
0
How do we solve the geometric coincidence problem? I need a semi-cylinder that fits into the cuboid but if I use the cuboid and the cylinder directly it's geometrically problematic
 
Engineering news on Phys.org
  • #2
I'm not quite following the question. MCNP does Constructive Solid Geometry. Shapes are supposed to intersect and then you tell it which volumes are what part of the problem.
 
  • #3
I set up four cubes but only two are displayed. In my setting, there should be cuboids in the middle and under the ring. Why？

QQ图片20230426151847.png
 

Attachments

  • A1++.txt
    322 bytes · Views: 90
  • #4
In a cell definition a positive surface typically means above or outside. A negative surface means below or inside. If you take a look at cell 3, you have -3 4, meaning below x=4 and at the same time above x=6. The space between x=4 and 6 is "3 -4". Now have a look at cell 4 and see if you can find something similar.
 
  • #5
Thank you very much Alex A, I got the X-axis wrong. The sign of 1, 2,3, and 4 surfaces in the surface card is wrong
 
  • #6
However, after I corrected the error of x axis, the modeling problem still occurred in cell card 1. Why is cell card 2 and cell card 1 written in the same way? cell1 caused the problem, but cell2 did not
 

Attachments

  • QQ图片20230427163840.png
    QQ图片20230427163840.png
    19.3 KB · Views: 73
  • QQ图片20230427163848.png
    QQ图片20230427163848.png
    28.7 KB · Views: 66
  • A1++.txt
    328 bytes · Views: 80
  • #7
MCNP seems happy. When I try the interactive plotter I see the full D. VisEd does not seem happy from your picture. Maybe VisEd does not like the comment. I do not see an error.
 

Similar threads

MCNP4C suppressing terminal/console window popping up?
    • Nuclear Engineering
Replies
3
Views
1K
MCNP code for Neutron Spectroscopy
    • Nuclear Engineering
Replies
17
Views
916
[MCNP] Lost too much Keff with Burnup card
    • Nuclear Engineering
Replies
5
Views
2K
MCNP Surface Tallies: F1 & F2 on Infinite Cylinders & Planes
    • Nuclear Engineering
Replies
5
Views
2K
MCNP and simple nuclear physics
    • Nuclear Engineering
Replies
9
Views
2K
How can I model both photons and neutrons with MCNP?
    • Nuclear Engineering
Replies
7
Views
2K
Can diffusion be modelled as one-dimensional in this problem?
    • Materials and Chemical Engineering
Replies
20
Views
392
Calculate polarization energy over a set of cuboids
    • Optics
Replies
5
Views
862
Building a Honeycomb Structure in MCNP: Error Solving
    • Nuclear Engineering
Replies
2
Views
2K
Time to empty gas cylinder (problem worked, but would like feedback)
    • Mechanical Engineering
Replies
7
Views
494

Hot Threads

Recent Insights

Back
Top