These should follow the naming conventions of the the other reactions.  All of the other reaction names are valid variable names in python / C++.  (This is because it let's you write neat expressions in Python like "total == scattering + absorption", and depending on the namespace that can be meaningful.)

`+` and `-` should probably go to `plus` and `minus`.  `14c` should probably go to `C14` to be consistent with `He3`.  Use underscores as separators where needed.  Ones which start with a number should likely be prefixed by `decay_`.  

I hope this helps.  As you pointed out, this needs to be documented better.