Add Script for GNDS Data Processing

[ahnaf-tahmid-chowdhury]

Description

Currently, there is no script available for processing GNDS files in the repository. Given the increasing use of GNDS in nuclear data, it would be beneficial to have a dedicated script to convert GNDS files into HDF5 libraries for OpenMC.

Proposal

I propose adding a script that:

• Converts GNDS files into HDF5 format.
• Integrates smoothly with existing OpenMC workflows.
• Provides documentation and examples for users to understand its usage.

Benefits

• Expands the versatility of OpenMC by supporting additional data formats.
• Encourages more users to utilize GNDS data for their simulations.

Let me know if this feature is worth considering!

[jon-proximafusion]

I would be keen to see this feature. I think it might also help avoid some of the nuclear data issues we see appeaing in ACE files occasionally. Would it be more suitable in Paul's endf-python package and then we wrap it in ipenmc incident neutron class

[paulromano]

If there is other software (e.g. Fudge) that can convert GNDS to ENDF, there's not a huge motivation for us to reinvent the wheel. If and when evaluators start putting data in evaluations that can only be represented in GNDS, then it may become a real issue but I don't think we're at that point yet.

Also, provided that NJOY adds support for GNDS, that's also something that we can leverage since we mostly take data from ACE files rather than ENDF files.