This is a good idea. I would like to support plutonium in nuclear science.
I have not played with any of the plutonium mods, so if I'm missing any, please let me know. From a quick mod portal search for "plutonium", Plutonium Energy seems to be the major one that is Factorio 2.0 compatible. So this is brainstorming for compatibility when that mod is also present.
It should be reasonably trivial to add a nuclear science pack cost to Plutonium Energy's technologies.
I could also add an alternative nuclear science pack recipe that requires fissile plutonium and offers a better science pack yield.
Potentially, I could add in a mod option that significantly nerfs the basic recipe to soft the require the player to setup plutonium breeding.
Please let me know your thoughts. It would also be great to get your input into the other comment thread about the other ingredients to the science pack.