Chicago Pile

The Chicago Pile is a crude Plutonium-production reactor in HBM's Nuclear Tech Mod.

It is a multiblock constructed out of Graphite blocks, which can then be drilled to insert a variety of rods, including natural Uranium fuel, Boron control, Radium neutron sources, and Plutonium rods. It does not produce power.

After the natural Uranium rods reach a certain amount of depletion, they transmute into Plutonium rods, which can be extracted and reprocessed into Reactor Grade Plutonium. While it is impossible for use in Nuclear Weapons without a SILEX, this Reactor-Grade plutonium can be used in fuel for power-producing reactors such as the ZIRNOX and the RBMK.

Construction
The Chicago Pile requires a significant amount of graphite blocks, which once placed can be drilled into with the hand drill to place an assortment of rods into. These rods include the Uranium rod, used as the fissile fuel that will also undergo transmutation; the neutron source rods, Radium-Beryllium and Plutonium, which kickstarts the reaction; and the Boron control rods, which absorb any neutrons that come into contact with it.

Graphite can be made either from pressing coke in a press, or processing coal blocks directly into graphite blocks in an Ore Acidizer. Uranium and Radium rods can be crafted from two iron plates and three billets of the appropriate material; Boron rods can be crafted from two boron ingots and one wood plank. Plutonium rods can only be transmuted from Uranium, but all rods can be recycled back into their constituent components.

The hand drill can be used to drill holes into the graphite or take core samples of the uranium fuel to determine the heat, depletion, and neutron flux of it; screwdrivers are used to extract rods. Both eventually break.

Neutrons
Neutrons are automatically produced by Plutonium and Radium neutron sources, which will spread out in 'rays' in every direction. Upon hitting a Uranium rod blocks, the rod will react and then cast rays of its own in every direction as well. The efficiency of this reaction depends on the distance travelled (at 1.5 blocks, the efficiency is greatest) and the heat of the rod (thermal expansion reduces the reaction by up to 50% at maximum heat). 'Rays' have a maximum range of 5 blocks.

Heat
All Uranium rod blocks have a heat value, with a maximum of 1000. The value of neutrons, after reacting, is added to the heat; if the maximum heat is reached, the pile will erupt into a fiery explosion. There is no way to increasee the cooling effect.

Depletion
Uranium rod blocks also have a depletion value, which the neutrons, after reacting, are added to. Upon reaching 50,000 (or 75,000 in 528 Mode), the Uranium rod will transmute into a Plutonium rod, which acts a neutron source and does not fission; however, the value of neutrons for each 'ray' is 3 instead of 1 for the regular radium source rod, making it a stronger source. Use this to your advantage.

Design
Because the Chicago Pile can only be passively cooled and the Boron control rods to absorb neutrons are manual, most safe designs are limited in their size and scope. Even then, there are designs that guarentee fast plutonium production. These designs often take the form of block-thin disks; as 'stacking' uranium rods, or placing several of them too close together, can lead to a runaway chain reaction, causing an explosion. Organizing the design in thin disks increases the amount of neutrons that escape the reactor, decreasing the chance that such a chain reaction will occur.

Spacing two or more disks apart sufficiently can also prevent a chain reaction. As the 'rays' from neutron sources and uranium rods are emitted, they will spread out with distance; reducing the chance that the neutrons will react with a uranium rod block.

Keep in mind that Uranium rods will still transmute into Plutonium rods, which emit more neutrons then typical radium rods. For pile assemblies that strike a delicate balance of neutrons, Boron control rods may be needed to limit reactivity via manual insertion.

Trivia

 * The Chicago Pile is based off of the real-life Chicago Pile 1, the world's first artifical nuclear reactor.
 * Unlike the Chicago Pile in NTM, the real life pile was mostly used for experiments on the properties of tritium and the neutron absorption cross section of various substances. Instead, the X-10 Graphite Reactor was the first nuclear reactor used for plutonium production.
 * Originally, the pile produced "regular"/"unenriched" Plutonium, which contained Plutonium-238. However, this was changed to Reactor Grade Plutonium, as the processing required made the Pile pointless as you could just use Uranium directly and save effort.
 * In 528 mode, 1 of the 3 billets in the Plutonium rod is nuclear waste.