Fission
This one's a biggie, and will probably span at least two posts, if not more, because there's a
lot of ground to cover. Fission is what I consider the breaking point of the mod, where you start
really getting some
serious juice. Once you become able to reliably run at least one high-pressure turbine, you can start working towards madness level: fusion. This is
especially true if you use ElectriCraft. Which I do. Extensively. Note for ElC users: go for superconductors when working with reactor-level electricity. While the loss might not be too terrible, considering the sheer amount of power you're getting, the current limitations can be annoying to deal with and, honestly, once you hit reactor level, you should be able to produce at least a few stacks of insulated, filled superconductors.
So, how does fission work? Well, you've got three main things that are omnipresent in fission-based reactors: fuel cores, boilers, and neutron reflectors. Fuel cores are obvious: they store fuel and are the main working part of your reactor. Boilers, running either water or ammonia, turn the heat of fission into steam, which runs your turbines. Neutron reflectors take up a somewhat special place: they, as the name suggests, reflect neutrons back from whence they came. Neutron flux causes fission, and more neutrons equals more fission, which in turn equals more heat and, finally, more power.
However, be very, very careful, as too
much fission is a far, far worse thing than too
little fission. If your reactor melts down, you will be left with a big hole (granted, not as big as IC2, but big enough to be a bother) beneath your reactor, radiation everywhere, and ludicrously toxic corium where parts of your reactor used to be. As you might guess, this is a
bad thing. Radiation kills all living things,
especially plant life. If you're running farms near a reactor that goes critical, you can say goodbye to farming there until you do some
massive cleanup.
There
are other, not as often-used (in my experience) parts that
can make reactors safer, however: control rods, coolant cells, and reactor CPUs. Coolant cells are the simplest: they take in coolant and keep the reactor from overheating. The downside is that this does
not make steam and, thus, does not make power, its only purpose is keeping the reactor cool. The control rods act as part of a failsafe mechanism: by triggering them, you can prevent neutron flow and, thus, stop the reactor in its tracks. The CPU (which requires 1kW per control rod) is very useful when using control rods as it can, on redstone signal, cause all rods in the connected reactor to fall into place at once and it can also do so during a SCRAM event, when reactor temperatures reach dangerous levels.
When it comes to fuel, the standard (non-breeder) fission reactor can take two varieties: U-235, or Pu-239. Plutonium (Pu-239) is more reactive than Uranium (U-235), and thus, is more likely to trigger fission when the core ticks and, thus, more likely to produce
more neutrons. Alas, this also means that plutonium-based reactors run hotter and require greater heat dissipation and safety measures than their uranium-based counterparts. Of course, this
also means that you tend to get more power per unit fuel out of plutonium than you do uranium. Plutonium also has the risk that, unless you're wearing a hazmat suit (and a
full one, at that), then you
will suffer radiation poisoning if you have it in your inventory, so
handle with care. The fuel stats are thus:
Uranium-235
- Fission chance: 25%
- Chance to deplete by +1%: 3%
- Chance to produce waste: 5%
- Temperature step: 20 degrees
Plutonium-239
- Fission chance: 30%
- Chance to deplete by +1%: 4%
- Chance to produce waste: 10%
- Temperature step: 30 degrees
As you can see, plutonium has a better chance of fission, but each update adds 30 degrees to the core's surroundings, 50% more than uranium. Again, this
does mean more power, but with double the waste and 33% faster depletion rate, there
are more considerations when making a plutonium-based reactor.
Every time fission occurs, a neutron burst is spawned and is sent out in any horizontal direction. This burst can collide with other fuel cores and have a chance to trigger fission there, as well. Therefore, more nearby cores means more fission, which leads to more heat, which leads to more power, but also more danger. The important thing is to balance the forces of fission and heat, giving your reactor enough places for heat to go (that aren't other fuel cores) so that the fuel cores don't overheat and meltdown while
also taking care to ensure that your
boilers don't overheat and blow up.