Fission Reactor

This page is for Fission Reactors in NuclearCraft. You may also be interested in reading the Fission Reactor section of the NuclearCraft tutorial or the Reactor Designs page for more specific info on designs that others have come up with.

Fission Reactors
A fission reactor consists of a controller and a reactor core. The core is then filled with your choice of Reactor Cells, Coolers and Moderator blocks. Building the frame of the core is simple, but choosing the right combination and configuration of parts to go inside is tricky!


 * 1) Start by building the reactor core frame out of Reactor Casing and Fission Ports if wanted.
 * 2) Place a Fission Controller alongside or within one of the walls of the frame.
 * 3) Place Reactor Cells, Moderator blocks (currently the only moderators are Graphite and Beryllium blocks) and Coolers inside the core.
 * 4) Insert a Fuel Rod into the controller.
 * 5) Apply a redstone signal to the controller to turn the reactor on.


 * The interior of the reactor core may have any size from 1x1x1 to 24x24x24. Any cuboid shape is valid; it doesn't need to be a cube.
 * Note that only the faces consist of reactor casing blocks - placing reactor casing along the edges will most often result in the controller being unable to determine the position and size of the reactor.

Constructing Your Reactor
This section details the mechanics of how NuclearCraft's fission reactor components interact.

Managing heat and power, while getting the best efficiency, is the core challenge of NuclearCraft's fission reactor.


 * Each block inside a Fission Reactor either creates power (RF) and heat (H), removes heat, or modifies the way in which the blocks interact.
 * The position of blocks relative to each other is very important. Some blocks get boosts from being adjacent to others, some won't work unless adjacent to another.

Fuel Calculator
Jox, a member of the NuclearCraft Discord server, created a spreadsheet that both assisted with Fission Reactor calculations and tabulated the products of fuel reprocessing. It was updated by the mod author to include information on which fuel is most efficient in the design being tested, and can be found here: Spreadsheet

An older spreadsheet by /u/Snarklord which is valid for NuclearCraft pre-2.9 can be found here: Spreadsheet

Reactor Core Blocks
The following blocks should be placed down inside the reactor core:

Reactor Cell
This is the main component that creates energy and heat.


 * When not adjacent to any other cell or moderator, each cell produces the base power and heat listed for the fuel you are using. For example, if using TBU fuel, which has a base power output of 60 RF/t and a base heat output of 18 H/t, a reactor containing a single cell will produce 60 RF/t and 18 H/t. A reactor containing two non-adjacent cells and using TBU fuel, will produce 120 RF/t and 36 H/t.


 * Any cell adjacent to at least one other has a higher efficiency and their power and heat output increases dramatically. In general, each cell adjacent to $$n$$ other cells produces $$(n + 1)$$ times the base fuel power output and $$\frac{(n + 1)(n + 2)}{2}$$ times the base fuel heat output. For example, a reactor with two adjacent cells and TBU fuel will have an efficiency of 200%, producing 240 RF/t and 108 H/t.

Moderator Blocks
Moderator blocks such as Graphite provide an efficiency boost but will also produce additional heat. Although moderators will generate additional heat wherever it is placed in the structure, it will only generate extra power if adjacent to at least one Reactor Cell.

Pre-2.9: The additional power generated per moderator block is equal to $$\frac{baseRF \times adjacentCells}{8}$$ RF/t, and the extra heat generated is $$\frac{baseHeat \times noCells}{16}$$ H/t, where $$baseRF$$ and $$baseHeat$$ are equal to the RF/t and H generated by the fuel used respectively. If the moderator block is not adjacent to any cells, the additional power will not be generated. In addition, when placed between two cells, the cells behave as if they were adjacent, becoming more efficient.

2.9 and onward: The additional power generated per moderator block is equal to $$\frac{baseRF \times cellEff}{6}$$ RF/t for each adjacent cell, where cellEff is the efficiency of the cell. Similarly, the extra heat generated is $$\frac{baseHeat \times cellEff}{3}$$ H/t. If it is not adjacent to any cells, additional power will not be generated and extra heat equal to the fuel's base heat output will be generated. In addition, if two cells are connected by a straight line of at most four moderator blocks, the cells behave as if they were adjacent, becoming more efficient.

Coolers
Coolers remove heat from the reactor core. There are several different types of cooler and each has its own set of conditions under which it operates.

Pre 2.9:

Post 2.9:


 * Active Fluid Cooler: This cooler requires liquid coolant to be piped into the reactor core via a Buffer. Inside the chamber, the fluids must be piped from the Buffer to the coolers. Active coolers cool the reactor at a maximum of 500% the rate of the regular passive coolers of the same type but any liquid piped into them is consumed at a maximum rate of 0.25 mB/t (0.5 mB/t in v2.8 onward). Water will be the most practical for most players, but more expensive coolants are extremely effective at removing heat.

Notes:
 * If a cooler's conditions are not met, the block will not cool anything!
 * Sub-conditions must also be met! E.g., a Gold Cooler must be placed against an active water cooler. If the water cooler isn't against the casing, then it isn't active so it does nothing, and neither does the gold cooler.
 * Enderium and Cryothermium coolers require Thermal Expansion to be installed.

Reactor Configuration
The main challenge in NuclearCraft is figuring out how to arrange the cells, moderator blocks, and coolers. Placing cells next to each other boosts efficiency but results in a lot more heat. Using graphite blocks can increase the efficiency and add space to insert more coolers. Diamond, Emerald and Cryotheum coolers do a lot of cooling, but may be too expensive for you before late mid-game.

This subsection is for suggestions and tips on how to proceed with this task. Your mileage will vary so be careful. In this process you'll have to go in and out of the reactor core quite often so you might want to replace two Reactor Casing blocks with a Reactor Door.

After you've built the reactor and chosen which fuel you want to use, place down a single reactor cell then put in a Fuel Rod in the Controller. The Controller will show the figures for efficiency, power, and heat. Now go back in and place another Reactor Cell. Check the controller and see how the numbers have changed. You'll need to experiment a lot!

Note: A lot of the info in the bullet points below is no longer true in later versions of NuclearCraft (v2.9a and above) due to the changes made to the fission reactor rules.
 * If you can afford them, put 8 Enderium coolers in the chamber, one in each corner. That's 32 Enderium Ingots in total.
 * Coolers can share other coolers. For example, you can place a Redstone Cooler against any or all faces of a reactor cell.
 * Diamond Coolers must be placed in a cross pattern, between 4 Water Coolers. This pattern can be tessellated; that is, two Diamond Coolers can share two Water Coolers.
 * Think in three dimensions! Just because you can repeat a pattern, doesn't mean you should. For example, you have an exposed face of a Reactor Cell. Don't just put a Redstone Cooler there. Look around to see what other blocks are nearby. It may be smarter to use a Lapis cooler (100 H/t) than a Redstone Cooler (80 H/t) because there's a reactor wall nearby.
 * Think in combinations! When you're looking at a space in the reactor, try to think of all combinations and see which is the best. Although a Lapis Cooler is more effective than a Redstone Cooler, it might be smarter to use a Gold Cooler because there are Redstone and Water coolers nearby.
 * Be careful with active coolers. You need piping internally to take the fluids from the Reactor Port to the Cooler. While this can be of great benefit (doubling the effectiveness of some coolers), the space required to run the pipes might be more effectively used for passive coolers.
 * A reactor can have a lot of empty space if you want. If your chamber is much larger than needed for the number of Reactor Cells you're using, you'll have room to run pipes to active coolers. However you won't be able to use as many of the coolers that require to be touching a Reactor Casing.
 * You can put "foreign objects" like torches and chests inside a reactor.
 * You can use transparent reactor casings if you like, although unless you have piping or other stuff inside, there won't be much to look at.




 * The most efficient reactor core design consists of alternating Graphite and Reactor cells in the pattern . This design can be repeated in three dimensions and indefinitely for infinitely increasing efficiency. 1 9x9 layer of this pattern will generate 922% efficiency, and a 9x9x9 core has an efficiency of 5126%. However, this also dramatically increases heat and power, and active cooling is a must for cores bigger than 5x5x5.

Saving Fuel
A fission reactor will continue to operate even when the internal energy buffer is full. To avoid wasting fuel, a tool such as the RF Monitor from RFTools can be employed to send a redstone signal to the Fission Controller if the buffer is below a certain percentage. Note that the presence of a redstone signal turns the reactor on.

Preventing a Meltdown
A fission reactor that overheats will undergo a meltdown &emdash;random blocks of the structure will melt into Corium. Placed against the controller block, a comparator will emit a signal if the heat level exceeds 50% (this can be altered in the mod's config file). By inverting this signal and feeding it back into the controller, the reactor will only operate if the heat level is below 50%. Note: This doesn't save fuel, it just prevents the reactor from melting down.