I've been playing IndustrialCraft since IC1, so I've seen the overhaul of nuclear power; overall I'm somewhat satisfied. Still, I've done and unhealthy amount of research into all things nuclear - to the point I could confidently build a reactor in my back yard - and as such, a few parts of the new reactor system still disappoint me. Obviously, part of good game design is to balance reality with what is fun; I'm basically going to outline nuclear power IRL, and then make some suggestions to how IC2 nuclear power could be made even more awesome.
The Nuclear Fuel Cycle IRL:
Generally speaking, there are 3 different elements of interest when talking about nuclear power: Uranium, Plutonium, and Thorium. Of those, each consists of a number of Isotopes. If you'll remember back to high school chemistry, every atom consists of a number of protons, neutrons, and electrons. The number of protons determines when element the atom is; Uranium contains 92 protons. The number of neutrons determines the isotope, which in turn determines the atom's usefulness in a nuclear reaction. The difference between the number of protons and the number of electrons determines the charge, which is mostly irrelevant to what we're talking about. Coming back to isotopes, they are expressed as the element's name, followed by the sum of the atom's protons and neutrons.
Unfortunately for us, nature does not cooperate in providing us the elements we need for nuclear energy. Specifically, and nuclear program starts by refining the isotope U-235(Uranium with 235 - 92 neutrons). It occours in natural uranium in very small quantities - roughly 1 part per 1700, if I remember correctly. After refining the Uranium Ore into elemental (nothing but various isotopes of the element Uranium) Uranium, we have what is called "Yellow Cake Uranium". Simplifying slightly, this Yellow Cake is then put into a high tech, high speed, gas centrifuge which separates the valuable and fissile U-235 from the U-238. U-238 is useful in it's own right, but we need the U-235 first.
Upon ammassing sufficent U-235, we're ready to build our first nuclear reactor. Smart people will build what is called a breeder reactor. Without going too in depth on how it all works, excess neutrons from the fission of U-235 can be used to bombard some of that extra U-238, turning it into Plutonium-239 - which just so happens to be more valuable than U-235. After a little bit of processing, that Plutonium we just made can be used to fuel the next nuclear fuel cycle, repeat ad infinitum.
There is also Thorium, another naturally occurring element that can be bread into nuclear fuel. It is more common than uranium, but you have to have a working breeder reactor to extract any useful fuel from it. Regardless, it is a promising fuel, and India is looking heavily into it to fuel there nuclear power program.
-Add Thorium as an ore w/ about 2X the frequency of uranium
-Make Uranium ore be processed in a macerator to yield uranium dust
-Add a centrifuge as a machine
-Then have the dust go through the centrifuge to separate U-235/U-238
-Then compress into ingots
-Let the player breed plutonium fuel in their reactor
-Consider including RTGs as a tier 3 mobile power source
-Add a fallout block that damages player not wearing full nano/quantum armor, has a slight yellow/green haze, and is otherwise passible
-Rework nukes to only be built with U-235 or Pu-239
-Nukes should make a bigger crater than reactors, just sayin'
-Thermonuclear devices? Even bigger boom?
I'd be happy to help with any of the nuclear stuff; email me at my registered email if anyone is interested.