is there a way to add differnt fissile material types like from enchanted nuclear like neptunium uranium 233 or plutonium

It depends what kind of thing you want - doing so would have to be part of a mod - there is no way of doing this as a setting, however, if you want to make a mod to do this, it shouldn't be too difficult, although there is no elegant way of doing all of them. If you look under prototypes/nukes/compatibility/add-basic-uranium-nukes.lua that should be a reasonable approach to adding new ways of making the existing warheads.

Ah, I've finally actually worked out what you were asking. I'll absolutely do plutonium - its a pretty simple change honestly.