The default nuclear library used in OpenMC is nndc_hdf5 from ENDF/B-VII.1.
It contains neutron and photon nuclear data library.
As the OpenMC is mainly used for fission related calculation, some of the nuclides are missing from the defaul neutron nuclear library.
Such as C12, C13 and O18.
I am trying to use OpenMC to run fusion problem, therefore, add the missing nuclides to the nuclear library is a necessary step.
And the process is quite simple.
Found a missing nuclide
Sometimes when you run the problem, OpenMC reports a error such as:
1 | ERROR: Could not find nuclide O18 in cross_sections.xml. |
That means the O18 is missing in your nuclear library.
Generate h5 nuc file for specific nuclide
OpenMC provide a script openmc-ace-to-hdf5 to convert ACE format nuclear library to OpenMC h5 nuclear library.
For examle, assuming that you have downloaded the FENDL3.1d neutron library, you can create the O18.h5 library using:
1 | openmc-ace-to-hdf5 08O_18 |
More usage of openmc-ace-to-hdf5 can refer to the official tutorial.
Add the path to cross_sections.xml
Once the wanted nuclear library is created, you need to add the path of the nuclide to corss_sections.xml.
Then that’s all set!
Note: We can create all the FENDL3.1d nuclear library and add the path before the defaul neutron library paths.
After that, OpenMC will find the FENDL3.1d neutron library first.