I'm curious actually, is uranium processing not deterministic? Does it not depend on the seed? Or is that seed only for the map and does it not influence other random events like biters and uranium?
The first multiplayer versions basically synchronised with each other and then ran independently, just executing the keyboard input from other players basically. No central server calling the shots. This was hell development-wise, but I think that concept hasn't changed too much actually: you may have a central server that tells your client whether you can really pick up an item from a chest or whether it's already gone, but the local simulation is still local (it's not as if there is an incoming video stream or stream of all entities that have moved; far from it, it's a handful of kilobytes per second). The random engines almost have to be synchronized as I never noticed more data traffic during biter attacks or such.
Of course it's still deterministic. It's a computer program, so it has to be deterministic. Multiplayer still uses a lockstep simulation, so all clients must compute the same random outcome.
But it does introduce an element of randomness that isn't present anywhere else in the game. Every other recipe in the game has fixed inputs and outputs with known ratios, and often very nice ratios. Put in two iron plates and get out a gear. Put in one copper plate and get out two copper wires.
The randomness in uranium processing is used to simulate the cascades of centrifuges used for isotope enrichment without having to track the enrichment of every single lump of uranium, and without having to introduce a hundred different types of uranium ore items. Instead you have a 0.7% chance of getting a lump of uranium-235 every time you process some uranium ore; the rest of the time you get uranium-238. 235 is used for fuel, 238 is used for ammo and for further enrichment.
It's clear what you meant, but I just wanted to touch on a nuance: Skinner boxes can be deterministic. "Skinner box" in the context of games generally just refers to the game design feeding you a steady drip of reward cycles.
