Source-checkedTechnology & automation

Colossal Reactors

by Unfamily · for Minecraft

Build and run large multiblock nuclear reactors to generate power.

796Downloads
3 mo agoLast updated
MITLicense
NeoForgeLoaders

About Colossal Reactors

From Modrinth

Build and run large multiblock nuclear reactors to generate power.

Colossal Reactors

Build and run large multiblock nuclear reactors to generate power. Feed them fuel and coolant, then extract RF from a power port. Use the Reactor Builder to automate construction, the Melter to turn items into fluids, and Heating Coils to supply heat.

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Reactor

A reactor is a hollow box made of reactor casing and reactor glass. Inside you place reactor rods (they hold the fuel) and coolant: either blocks (e.g. diamond blocks, water blocks) or liquids (e.g. water). The better the coolant, the more power and efficiency you get.

  • Reactor Controller — Place it on the reactor (e.g. on top). Open it to see status, stability, energy output, and to reboot the multiblock.
  • Rod Controller — Controls how far the rods are inserted. More insertion = more power and heat; you balance this with coolant to avoid overheating.
  • Resource Port — Insert solid fuel and coolant fluid, and extract nuclear waste and spent coolant.
  • Power Port — Connect cables here to take out RF.
  • Redstone Port — Optional. Use it to turn the reactor on or off with redstone, or to require a redstone signal to run.

You need fuel (e.g. uranium-based) and a way to keep the reactor cool. The controller screen shows you if the reactor is valid and how much power it produces.

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Reactor Builder

The Reactor Builder automates building the reactor multiblock. You set the size (width, depth, height), choose a rod pattern, and fill its inventory with casing, glass, reactor rods, rod controllers, and optionally coolant blocks or a tank of coolant fluid.

When you start the build, it places the frame, then rod controllers and rods, then coolant (liquid from the tank or blocks from inventory) according to the coolant type you selected in the builder. It will not place blocks where you already have liquid coolant, and it only places the coolant type you chose (e.g. only diamond blocks if you selected that option).

Use it to build colossal reactors quickly and consistently.

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Melter

The Melter turns items into fluids (e.g. ingots into molten metal). It has a single item slot and a fluid tank. It does not work alone: it needs a heat source on at least one of its sides (up, down, or the four horizontals). Valid heat sources are lava, campfires, torches, or Heating Coils. Heating Coils give the best heat and are the intended way to run the Melter; lava and campfires work too. More heated sides mean faster melting.

Place the Melter, put heat next to it (e.g. Heating Coils, or lava, or campfires), feed it the right items and it will produce the corresponding fluid. You can pull the fluid out with pipes from the front face.

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Heating Coils

Heating Coils are what make the Melter work. They must be placed next to the Melter (any of the six sides). Each coil type “burns” something to produce heat:

  • Resource Heating Coil — Consumes fluids and/or items from its front face (e.g. water, fuel items). You pipe in what it needs; it heats up and passes heat to the Melter.
  • Energy Heating Coil — Consumes RF from its front face. Pipe power in; it heats the Melter with no fluids or items.

So you can run the Melter with steam and fuel (resource coil) or with pure power (energy coil). Coils have a simple interface on the front to configure input and, for the resource coil, what to consume.

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Summary

  • Reactor — Multiblock that burns fuel and coolant to make RF; you manage rods and coolant for power and stability.
  • Reactor Builder — Builds the reactor for you from inventory and tank; you choose size, rod layout, and coolant type.
  • Melter — Melts items into fluids; needs heat from adjacent lava, campfires, torches, or Heating Coils.
  • Heating Coils — Supply that heat using either fluids/items (resource coil) or RF (energy coil).

Highlights

From source data

Game versions

Supports 2 Minecraft versions, the newest being 26.1.2.

Loaders

Runs on NeoForge.

Footprint

Rated a light load on a server.

Colossal Reactors on Nxeon

From our catalogue
One-click install
Supported on Nxeon Minecraft servers. We download it from Modrinth, place it, and restart the server.
Server side
Required on the server
Server type needed
NeoForge
Server load
light
Smallest plan we suggest
Minecraft — 2 GB (2 GB RAM). This follows our own load rating above, not a benchmark.
Latest build
2.2.2.0.2, released 2026-08-13

Game versions by loader

LoaderGame versionsNewest
NeoForge1.21.1 to 26.1.2 (2 versions)26.1.2

From 5 recorded builds of Colossal Reactors.

Recent builds

BuildReleasedGame versionsLoaders
2.2.2.0.22026-08-1326.1.2NeoForge
2.3.2.0.22026-08-131.21.1NeoForge
2.2.2.0.12026-07-0626.1.2NeoForge
2.3.2.0.02026-07-061.21.1NeoForge
2.3.1.0.02026-07-051.21.1NeoForge

Dependencies

  • Required: modrinth project y16HgCOF (modrinth, not in our catalogue)
  • Required: modrinth project p19vrgc2 (modrinth, not in our catalogue)
  • Optional: modrinth project Ck4E7v7R (modrinth, not in our catalogue)

Declared by the newest build that lists any. Required ones are installed with it on one-click installs.

Run Colossal Reactors on a Minecraft server

Pick a server or deploy a new one above; it is installed in one click.

What kind of mod it is

From the catalog
Listed on Modrinth as “Mods”

Technology & automation

Machines, power, logistics and automation.

Runs on your server

From source side support

Modrinth lists Colossal Reactors as required on the server. Check its Modrinth page to see whether players need it too.

Compatibility

Game
Minecraft
Loaders
NeoForge
Runs on
Serverrequired on the server
Game versions
26.1.2 and 1 earlier

Verified at the source

  • ✓ModrinthOfficial listing, checked 2026-10-03Open ↗
  • ✓AuthorUnfamily, as published on Modrinth
  • ✓LicenseMITFree

Colossal Reactors, answered

Generated from the mod’s own source data.

Do my players need to install Colossal Reactors?

Modrinth lists Colossal Reactors as required on the server. Check its Modrinth page to see whether players need it too.

Which loaders does it support?

NeoForge.

Is it free?

Yes. Colossal Reactors is free to download from Modrinth. Its license is MIT.

How do I add it to my Nxeon server?

Use “Add to a server” on this page, or open NxLabs from your dashboard. We install it, restart your server and switch it on.

NxLabs

Run Colossal Reactors on a Minecraft server.

Deploy in about a minute from $4.99 a month, then add Colossal Reactors in one click.