Realistic Reactors

Add realistic nuclear reactors including a breeder reactor type and cooling tower. The reactors must be controlled through integrated circuit interface signals. The thermal energy output is dynamic and depends on reactor core temperature. The reactors require sophisticated designs of their cooling system and heat-pipe network. If the operational conditions aren't met then a reactor core meltdown with dangerous consequences occurs

a day ago
0.16 - 1.1
6 years ago
Latest Version:
3.1.5 (a day ago)
Factorio version:
0.16 - 1.1
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We introduce a nuclear reactor, a breeder reactor and a cooling tower. The nuclear reactor type has high power output while the breeder reactor type has medium power output and produces bonus materials. The thermal energy output of both reactor types as well as fuel efficiencies are dynamic and depend on operational temperature. The reactors have to be controlled with signals through the integrated circuit interface and depend on the cooling infrastructure through the Emergency Core Cooling System (ECCS) interface. Without cooling the reactor core will finally overheat and cause a meltdown. Cooling towers are designed to cool down hot water or steam coming from the ECCS or other parts of the plant. Physical layout of the power plant also plays a significant role.

Reactor operation

Starting and stopping

To start a nuclear reactor insert fuel cells and send the Start Control Signal to the circuit interface of the reactor. The reactor will start up and produce heat at a certain efficiency (see the two corresponding signals on the circuit interface).
To shut down the reactor either let it run out of fuel cells or send the SCRAM Control Signal to the reactor circuit interface.
Be aware that the SCRAM process takes some time and the reactor will still produce heat until it is fully stopped.

The point of maximum output and efficiency

Power output and fuel efficiency are changing dynamically depending on the reactor core temperature and the number of connected neighbor reactors. Additionally, the output of extra empty fuel cells of the breeder reactor type changes according to the temperature. To connect a reactor neighbor simply connect them with heat-pipes into one heat network. The reactors don't have to touch each other.

There are two possible options how output and efficiency are calculated, which can be changed in the settings.
By default Ownly's formulas will be used. In short this means: the hotter, the better. The higher the reactor core temperature is, the higher power output and fuel efficiency will be.
The alternative Ingo's formulas work a little different. Power output will also increase with higher core temperature, but efficiency will have a certain maximum, after which it will start to drop quickly again.

Reactor core meltdown

When the reactor core reaches 1000°C a reactor core meltdown is caused. The reactor explodes and leaves a ruin behind. That ruin produces permanent radiation around and generates radioactive clouds. These clouds pollute large areas around the reactor ruin. The radiation effect is damage to all lifeforms in proximity. To stop the radiation spreading, a sarcophagus must be built over the reactor ruin, then the radiation will slowly decay.


Find more details about Realistic Reactors operation in the forum post, the «FAQ» section and the DOCUMENTATION folder of the mod archive. Finally, talk to us! Our communication channel is the «Discussion» section of the «Realistic Reactors» mod page.

Supported languages

  • English
  • German
  • Russian
  • Korean

Supported mods


  • limited compatibility with mods which modify the connections or sizes of heat-pipe entities (e.g. Schall Pipe Scaling and similar) – when using such mods with Realistic Reactors please make sure the vanilla heat-pipes are used for the reactor heat-pipe network
  • blueprints made with RealisticReactors before version 3.0.0 need to be updated due to fixes in the reactor's combinator network interface
  • please report on our mod discussion page if any incompatibilities are discovered

Included materials


This mod was made by dodo.the.last, max2344, IngoKnieto, OwnlyMe and published under the MIT license.


Original idea and implementation by IngoKnieto and OwnlyMe.
Thanks to GotLag for the original reactors mod, which this mod is based upon.
Thanks to Sigma1 for making the awesome cooling tower picture.
The refactored version 3 was made by dodo.the.last and max2344 who are currently maintaining the mod.
The Korean translation was made by x2605.


The information on this mod page represents the state of the current release and might be updated without prior notification or public announcement. Please refer to the «Documentation» section of this page for details.