Run
terminates with Lost Particles on a Rotated Universe.
| Anomaly: | The run dies with lost particles on a
rotated universe. |
| History: | Submitted by user. |
| Versions affected: | MCNP5, MCNPX, MCNP6 |
| Impact: | Run terminates with Lost Particles |
| Work Around: | Remove duplicate surfaces on the fill that are also on the universe. |
Steps required to reproduce this anomaly:
Note: Run this example in the RSICC release of each of these codes.
About the Input file:
A cylinder inside a box. The height of the cylinder is equal to the height of the box (50 cm). The universe is rotated. Notice that two numbers are assigned to the top and bottom z surfaces. This causes MCNP to loose particles.
Click here to download the input file, iddt4 (2 kb).
Note the surface definition for surfaces 2 and 3 appear twice. The work-around definition is commented out.
Process to Produce Anomaly:
Verify that the surface definition for surfaces 2 and 3 are the definition with the $ comment: $lost particles on rotation
Run the input file in MCNP5 and/or MCNPX and/or MCNP6 verify the result.
Work around:
Modify the cell description so the duplicate surface is removed.
Click here to download the input file, iddt4a (2 kb).
Verify that the surface definition for surfaces 2 and 3 are not the definition with the $ comment:
Process to Demonstrate Work Around.:
Run the input file in MCNP5 and/or MCNPX and/or MCNP6 and verify the result.
Results obtained from our test:
MCNP6 fails. Run is terminated because 10 particles got lost.
By replacing the macrobody surface with facet 1.1, MCNP6 runs to completion.
