Sense your are doing tweaking with K2 and nuclear fuel here are some ideas for the two mods to help with compatibly.

• Rehide the nuclear fuel recipes for some reason nuclear fuel reenables them these two recipes should not be present.
• tweak plutonium recipe for atomic bomb to match changes for the uranium one (except the uranium part)
• see if you can get the recipe image for the atomic bomb to match the one in K2 based on the heavy rocket
• add plutonium recipe for the nuclear shell and nuclear turret rocket so koverex is not needed
• add radiation damage for plutonium and the breeder cells it currently doesn't harm the player while holding it
• For the SMR Mk3 replace the portable fusion reactors with the same amount of portable nuclear reactors as they nuclear reactors not fusion reactors.