Problem in converting B10 ACE file to hdf5 file using

Hi all,
I am a beginner in using openMC. When I used to convert Lib80x ACE files to the respective Hdf5 files for use in openMC, error is encountered saying that
Converting: openmc/Lib80x/B/5010.800nc
Traceback (most recent call last):
File “”, line 83, in
data =, ‘mcnp’)
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/”, line 587, in from_ace
ace = get_table(ace_or_filename)
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/”, line 188, in get_table
return Library(filename).tables[0]
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/”, line 241, in init
self._read_ascii(fh, table_names, verbose)
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/”, line 416, in _read_ascii
assert xss.size == nxs[1] + 1
Kindly help to resolve the issue.

Hi @swathythila2. There was an error in the original ENDF/B-VIII.0 evaluation for B10 that leads to some strange behavior in the ACE file, which is why it trips up OpenMC when trying to parse the file. That being said, the script has some logic to modify the B10 files:

I’m not sure why you’re still seeing this error when it should have been accounted for. In any event, we have pregenerated HDF5 libraries (including the converted Lib80x) available here that should give you what you need.

Dear Sir,
Thank you for your kind and prompt reply.
Yeah, I could understand that the additional script is to take care of error in the original ENDF/B file. But, I am also not sure why I am getting this error message. Actually, I wanted to learn the basic things starting from the conversion of ACE to HDF5 files. That’s why I tried this.
Anyhow, I have taken boron files from the link which you have shared.
Thanks for sharing the same.