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Nuclear-Verification-and-Disarmament / ONIX

ONIX is an open-source depletion software for nuclear reactor simulations and nuclear archaeology. It is written in Python 3 and offers coupling with the open-source transport code OpenMC.
https://onix-documentation.readthedocs.io/en/latest/
MIT License
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Default decay library missing entries #11

Open Rademacher opened 2 years ago

Rademacher commented 2 years ago

The default decay library/ENDF-VIII reduced decay lib coming with ONIX appears to be missing data for a number of excited states even though they are potentially being produced/production cross sections for them exist. The entries are present in the not yet reduced libraries, and the problem only occurs for states generated through (n,gamma)X reactions - states stemming from decays are all present. I'd assume there is a related bug in the script doing the reduction - I haven't been able to find which one that is though.

Here is the list of missing states: Ba-133, Yb-176, Lu-176, Hf-177, Hf-178, Hf-179, Hf-180, Hf-182, Ta-182, W-183, W-185, Re-188 (and then also Re-188), Os-189, Os-190, Os-191, Os-192, Ir-192, Ir-193, Pt-193, Pt-195, Pt-197, Pt-199 (and then also Pt-199), Au-198, Hg-199, Pb-207, Po-211, Pu-237, Bk-248

As a special case, Th-229* is in fact not part of ENDFVIII, but present in other libraries.

Rademacher commented 2 years ago

For now I have manually added the missing decay data from the not yet reduced ENDFVIII decay library (with the exception of Th-229*, this I took from JEFF3.3) - see #12. Long-term we should try to figure where this came from, and maybe check how much of a difference this makes/if we need to check old results.

jung-benjamin commented 1 month ago

I have found a couple more nuclides that are created by fission (in ONIX fission yield library) but do not have any decay data in the default decay library. Although some of these nuclides are stable, most of them are not.

It is not immediately clear to me what the best way to deal with these nuclides is. To handle them correctly, new decay modes, such as (beta,n) and double beta would likely need to be implemented and data for the decay products added as well. missing_decay_data.json