Enable fission heating tallies in the random ray solver

[nuclearkevin]

Description

This PR adds tally support for fission heating (kappa-fission) in the random ray solver. This includes additions to the automagic multi-group cross section setup to generate heating cross sections. A new test has been added to hit the changes (random_ray_auto_convert_kappa_fission).

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[nuclearkevin]

It seems as if the test failures are caused by gcovr failing to generate C++ coverage. I don't think this has anything to do with the changes here (#3702 seems to be running into the same issue). If anyone could provide advice on getting gcovr to cooperate it would be greatly appreciated!

[paulromano]

@nuclearkevin I have two PRs (#3715 and #3716), one or both of which should resolve the gcovr issue. Please wait on one of those to be merged; at that point, retriggering the CI here should pass since it always uses a merge commit with develop (i.e., you don't need to update your branch).

[GuySten]

I saw that in 52fea6f you decided generating kappa-fission should be optional.
Until (if ever) we have coupled neutron and photon multigroup libraries, kappa-fission score is the best method for power normalization so it makes more sense to me to include this score by default and get rid of the gen_kappa_fission argument.

EDIT:
In any case, If you decide that nonetheless it should not be default I suggest using additional_scores keyword argument
instead of gen_kappa_fission.

[jtramm]

Looks good to me -- thanks for submitting this!

Only minor comment is on making the kappa_fission on always rather than adding another option for it. I know the default is on but I'm comfortable with just forcing this tally rather than adding more arguments/options to the interface. Let me know if there's another angle to this though that you can see @nuclearkevin!

[nuclearkevin]

Once cell density support is merged, I'll update the kappa-fission tally here to include it.

[nuclearkevin]

Added the multiplication by the cell density to this PR. Should be good for another round of review once the tests pass.

[nuclearkevin]

@jtramm I believe this is ready for another round of review when you have the time :)

[jtramm]

Looks good @nuclearkevin - thanks for making the changes!