Openmc-ace-to-hdf5 error

User Support
1

Hi All,
I’m trying to convert ACE MCNP cross-sections into HDF5 format.
The command is the following:
openmc-ace-to-hdf5 -d ./ --xsdir …/mu2e_xsdata/xsdirendf80

Unfortunately, the script does not start returning the following error:
Traceback (most recent call last):
File “/usr/local/bin/openmc-ace-to-hdf5”, line 73, in
if not os.path.exists(path):
File “/usr/lib/python3.5/genericpath.py”, line 19, in exists
os.stat(path)
TypeError: argument should be string, bytes or integer, not PosixPath

I can’t figure out what’s the problem. I’m using the script released with version 0.12.0 of the code.
Let me know if more information is necessary.
Thanks
Valerio

2

It looks like the openmc-ace-to-hdf5 script does not support your Python version (3.5). The os.path.exists function started accepting path-like objects in Python 3.6. Are you able to use Python 3.6 or higher? If not, you can try copying the openmc-ace-to-hdf5 script somewhere else and modifying the problematic line (73) to:

if not os.path.exists(str(path)):
3

Thanks Paul,

that’s probably the problem, as the same script worked perfectly on a different machine with python 3.6.9.

Modifying row 73 let’s the script start but then new errors are appearing:

/home/debian/.local/lib/python3.5/site-packages/openmc/data/energy_distribution.py:1246: UserWarning: Interpolation scheme for continuous tabular distribution is not histogram or linear-linear.
warn("Interpolation scheme for continuous tabular distribution "
Converting 1001.710nc (ACE) to H1 (HDF5)
Converting 1001.711nc (ACE) to H1 (HDF5)
/home/debian/.local/lib/python3.5/site-packages/openmc/data/neutron.py:284: UserWarning: Tried to add cross sections for MT=1 at T=600K but this reaction doesn’t exist.
“reaction doesn’t exist.”.format(mt, strT))
/home/debian/.local/lib/python3.5/site-packages/openmc/data/neutron.py:284: UserWarning: Tried to add cross sections for MT=101 at T=600K but this reaction doesn’t exist.
“reaction doesn’t exist.”.format(mt, strT))
Traceback (most recent call last):
File “/usr/local/bin/openmc-ace-to-hdf5”, line 126, in
data.export_to_hdf5(converted[name] + ‘_1’, ‘w’, libver=args.libver)
TypeError: unsupported operand type(s) for +: ‘PosixPath’ and ‘str’

This is now less important as I was able to convert the cross section on the machine with python 3.6.9. Nevertheless, the warnings related to not existing reactions where appearing also there.

/home/debian/.local/lib/python3.5/site-packages/openmc/data/neutron.py:284: UserWarning: Tried to add cross sections for MT=1 at T=600K but this reaction doesn’t exist.
“reaction doesn’t exist.”.format(mt, strT))
/home/debian/.local/lib/python3.5/site-packages/openmc/data/neutron.py:284: UserWarning: Tried to add cross sections for MT=101 at T=600K but this reaction doesn’t exist.
“reaction doesn’t exist.”.format(mt, strT))

Is it something to be worried?

Thanks again

Valerio

4

No, in this case, I wouldn’t be worried about the messages about these missing reactions. MT=1 and MT=101 correspond to the total cross section and the total neutron disappearance cross section, respectively. Both of those are redundant reactions that are recalculated as needed anyway.

5

Thanks a lot.

Valerio