# Problem in converting B10 ACE file to hdf5 file using convert\_lib80x.py

**URL:** <https://openmc.discourse.group/t/problem-in-converting-b10-ace-file-to-hdf5-file-using-convert-lib80x-py/1425>\
**Category:** User Support\
**Created:** [September 14, 2021, 7:26am UTC](https://openmc.discourse.group/t/problem-in-converting-b10-ace-file-to-hdf5-file-using-convert-lib80x-py/1425 "2021-09-14T07:26:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![swathythila2](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@swathythila2](https://openmc.discourse.group/u/swathythila2)\
**Post date:** [September 14, 2021, 7:26am UTC](https://openmc.discourse.group/t/problem-in-converting-b10-ace-file-to-hdf5-file-using-convert-lib80x-py/1425/1 "2021-09-14T07:26:39Z")

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Hi all,  
I am a beginner in using openMC. When I used convert\_lib80x.py 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 “convert\_lib80x.py”, line 83, in   
data = openmc.data.IncidentNeutron.from\_ace(p, ‘mcnp’)  
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/neutron.py”, line 587, in from\_ace  
ace = get\_table(ace\_or\_filename)  
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/ace.py”, line 188, in get\_table  
return Library(filename).tables[0]  
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/ace.py”, line 241, in **init**  
self.\_read\_ascii(fh, table\_names, verbose)  
File “/home/sri/thilagam/thils/openmc-build-0.11.0/openmc/data/ace.py”, line 416, in \_read\_ascii  
assert xss.size == nxs[1] + 1  
AssertionError  
Kindly help to resolve the issue.

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**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\
**Post date:** [September 14, 2021, 11:59am UTC](https://openmc.discourse.group/t/problem-in-converting-b10-ace-file-to-hdf5-file-using-convert-lib80x-py/1425/2 "2021-09-14T11:59:12Z")

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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 convert\_lib80x.py script has some logic to modify the B10 files:

> <https://github.com/openmc-dev/data/blob/bcc99743f5c0efa0d7f3821201e04a31f8fd1d0d/convert_lib80x.py#L51-L64>

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](https://openmc.org/lanl-data-libraries) that should give you what you need.

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**Author:** ![swathythila2](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@swathythila2](https://openmc.discourse.group/u/swathythila2)\
**Post date:** [September 14, 2021, 12:45pm UTC](https://openmc.discourse.group/t/problem-in-converting-b10-ace-file-to-hdf5-file-using-convert-lib80x-py/1425/3 "2021-09-14T12:45:18Z")

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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.