Including more reactions in generate chain script

[shimwell]

We have some nice scripts that use openmc.depletion to generate chain files.

The scripts like generate_endf71_chain.py call the Chain.from_endf

This class method has default arguments for the reactions which are reactions=('(n,2n)', '(n,3n)', '(n,4n)', '(n,gamma)', '(n,p)', '(n,a)'),

We call this method with out specifying reactions so therefore we make use of the defaults.

Should we instead add lots of reactions so that the chain file represents all the possible reactions?

[paulromano]

The short answer is yes, although the approach I would recommend is a little more involved. @pshriwise @eepeterson and I have discussed this at length and agreed that the right approach here is that the chain file itself should list all possible transmutation reactions and the downselection should instead take place at the point where the burnup matrix is being created. It will take a bit of refactoring to get there but this is definitely on my short list of things we need to take care of in the near-term. I'm planning on taking a crack at this in the next few months.

[shimwell]

Great to hear you three are on the case.

If it is of interested I processed the endf 7.1 chain with default and with all reactions and made two chain xml files for comparison.

chain_endfb71_with_default_and_all_reactions.zip

[shimwell]

Also now I have a "full" endf 8.0 chain file which might be handy
https://github.com/openmc-data-storage/openmc_data/blob/main/src/openmc_data/depletion/chain_endf_b8.0.xml