I've recently started work on a modpack myself, and the next thing on my list was going to be nuclear science! Seems like we thought alike on this measure!
We differ a bit on implementation, though. My thought was to make the science with U-238 because it's so much more abundant, especially pre-Kovarex (which I plan to make harder), and provides a good sink for that resource in the form of infinite tech research (which would include basically all the military tech, in my version). And it would also be used for a lot more tech, including Power Armor 2 and Mech Armor, Artillery, a more practical "dirty bomb" missile (and memetastic mini-nuke with fusion tech), tesla turrets, and the upgraded equipment. (A lot of this would be part of a general effort to make "nonessential" tech require combinations of two or more planets to craft.)
Options for the exact recipe are a bit wider since I plan to mod the Centrifuge to have pipe connections, because I also plan to make Kovarex require Fusion Plasma (and output Hot Flouroketone). Because I want to make U-235 an extremely important resource in endgame eventually, though the exact method remains TBD.
Anyways, I wanted to let you know in case you're interested in collaborating to make such a more extensive version of Nuclear Science, otherwise we could just keep notes on each others' work and keep making our own versions independantly.