In
MCNP6, a fixed, cell dependent, lattice source hangs.
| Anomaly: | In a fixed, cell dependent, lattice
source without i, j, k, indices MCNP6 hangs. |
| History: | Discovered in one of the example
problems in an MCNP6 workshop. |
| Versions affected: | MCNP5 and MCNPX run,
MCNP6 hangs. |
| Impact: | In MCNP6, must abort the run. |
| Work Around: | Use i, j, k, lattice indices in the source description. |
Steps required to reproduce this anomaly:
Note: Run this example in the RSICC release of each of these codes.
About the Input file:
A three by three xz lattice with a pitch of 20 cm. Each lattice cell is filled with an 8 cm radius sphere of water. A fixed source is volumetrically distributed through each of the nine spheres.
The definition of the source in this file is:
|
sdef cel=d1 rad=d2 |
Note that the si1 definition does not have i, j, k, lattice indices
Click here to download the input file, iddt2 (2 kb).
Process to Produce Anomaly:
Run the input file in MCNP5 and/or MCNPX and verify the result.
Run the input file in MCNP6 and verify that MCNP6 hangs. Type Ctrl-C multiple times until the run aborts.
Work around:
The definition of the source in the new file is:
|
sdef cel=d1 rad=d2 |
Note that the si1 definition does have i, j, k, lattice indices.
Click here to download the input file, iddt2a (2 kb).
Process to Demonstrate Work Around.:
Run the input file in MCNP5 and/or MCNPX and verify the result.
Run the input file in MCNP6 and verify the results.
Results obtained from our test:
MCNPX ran to completion:
MCNP6 hangs and the run has to be terminated:
With the altered source, MCNP6 now runs to completion.
