Hi all,
I was trying to scan plutonium on 1.6.4 build, and I realised that the recipe don't exist.
You could place a (very expensive) default cost for all materials in the game, maybe depending on the tier of the item, and then have the list with particular prices for the items you want to define.
In this way, we could create almost anything we need in game.
PD. To create plutonium, we spend lots of hours waiting, because the life cycle for uranium fuel is too high. We need another way, like this one, to get it (not a cheap way, but just not waiting).