Example Underhaul SFR
External Structure
Underhaul SFRs are built with a cuboidal casing (without edges). Transparent and standard casings are interchangable.
The Fission Controller can be placed on any edge or corner of the casing.
Fuel and power can be piped in/out of the controller, or any Fission Reactor Port. (Ports can be used in place of any casing block, except in the top and bottom faces)
The reactor can be turned on with a redstone signal to the controller. A comparator will read the total heat (if net heat > 0) or power (if net heat <= 0) stored in the reactor.
Fuels
Fuels are inserted directly into the reactor controller or through a reactor port.
Each Fuel has 3 stats:
- Base Power: The base power generation per cell (in RF/t)
- Base Heat: The base heat generation per cell
- Base Time: the time, in ticks, that one fuel item will last in a reactor with one fuel cell.
Internal Structure
Fission reactors are composed of Fuel Cells, Moderators, and Coolers.
Fuel Cells and Moderators make up the "Core" of every reactor.
 |
 |
 |
 |
| Reactor Cell (Fuel Cell) |
Graphite Block (Moderator) |
Beryllium Block (Moderator) |
Water Cooler (Cooler) |
|
Graphite and Beryllium moderators are functionally identical |
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Fuel Cells
Fuel cells have no special requirements, and can be placed anywhere within the reactor. If placed adjacent to each other, separated by up to 4 moderators, cells will generate extra energy and heat.
Energy increases linearly by 100% for each adjacent cell.
The base heat multiplier is (n+1)(n+2)/2, where n is the number of adjacent cells.
| Adjacent cells | Efficiency multiplier | Heat multiplier |
|---|---|---|
| 0 | 100% | 100% |
| 1 | 200% | 300% |
| 2 | 300% | 600% |
| 3 | 400% | 1000% |
| 4 | 500% | 1500% |
| 5 | 600% | 2100% |
| 6 | 700% | 2800% |
|
Actual values may vary based on mod configuration |
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For example, each cell below will receive a bonus for 1 adjacent cell.
Moderators
Moderators not only link cells together, as seen above, but also provide extra efficiency and heat bonuses to adjacent cells. They do not have to be between cells for this bonus to apply.
The moderator efficiency and heat bonuses are both linear. With n adjacent moderators, the efficiency bonus is n/6, while the heat bonus is n/3
| Adjacent cells | Efficiency bonus | Heat bonus |
|---|---|---|
| 0 | 0% | 0% |
| 1 | 17% | 33% |
| 2 | 33% | 67% |
| 3 | 50% | 100% |
| 4 | 67% | 133% |
| 5 | 83% | 167% |
| 6 | 100% | 200% |
|
(Shown values are rounded to the nearest percent) Actual values may vary based on mod configuration |
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For example, each cell below will receive a bonus for 1 adjacent moderator.
Moderators can only support coolers if they are adjacent to a cell.
For example, the beryllium moderators below can support coolers, but the graphite moderators cannot.
Coolers
Coolers are placed in the reactor to cool it down. Each cooler has placement rules and a cooling rate. If its rules are met, the cooler becomes active and can support other coolers.
Here is a list of all coolers and their stats:
| Cooler | Cooling Rate | Requirements |
|---|---|---|
|
Water Cooler
|
60 H/t | 1 Fuel Cell or 1 Moderator |
Redstone Cooler
|
90 H/t | 1 Fuel Cell |
Quartz Cooler
|
90 H/t | 1 Moderator |
Gold Cooler
|
120 H/t | 1 Water Cooler and 1 Redstone Cooler |
Glowstone Cooler
|
130 H/t | 2 Moderators |
Lapis Cooler
|
120 H/t | 1 Fuel Cell and 1 Casing |
Diamond Cooler
|
150 H/t | 1 Water Cooler and 1 Quartz Cooler |
Helium Cooler
|
140 H/t | Exactly 1 Redstone Cooler and 1 Casing |
Enderium Cooler
|
120 H/t | Exactly 3 Casing at one vertex |
Cryotheum Cooler
|
160 H/t | 2 Fuel Cells |
Iron Cooler
|
80 H/t | 1 Gold Cooler |
Emerald Cooler
|
160 H/t | 1 Moderator and 1 Fuel Cell |
Copper Cooler
|
80 H/t | 1 Glowstone Cooler |
Tin Cooler
|
120 H/t | Axial Lapis Coolers |
Magnesium Cooler
|
110 H/t | 1 Casing and 1 Moderator |
|
Actual values may vary based on mod configuration |
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There are a few types of placement rules:
- 2 Fuel Cells requires 2 or more fuel cells directly adjacent to this cooler
- Exactly 1 Redstone Cooler requires exactly 1 redstone cooler directly adjacent to this cooler
- Axial Lapis Coolers requires 2 lapis coolers on opposite sides of this cooler. There can be more than 2 lapis coolers, but at least 2 must be on opposite sides
- Exactly 3 Casing at one vertex requires exactly 3 adjacent casings, and that they must meet at one corner of this cooler. This means that the cooler can only be placed in the corner of a reactor that is 2x2x2 or larger.
Note that you cannot have casing blocks inside the reactor. Coolers that require casings must be on the outer edges of the reactor.
Active Cooling
Active coolers require a constant flow of liquid, but provide a massive boost in cooling. Most active coolers require the molten form of their passive counterparts. (For example, active iron coolers require molten iron). Active Enderium Coolers are the exception to this, using molten ender pearls intead of molten enderium.
Active coolers require 10mb/s of fluid (0.5mb/t)
Active coolers have the same placement requirements as their passive counterparts, but they cannot support other coolers.