CurseForge · Minecraft mod
NuclearCraft Reactor Builder
An automated reactor builder for NuclearCraft!
Quick answer
Which NuclearCraft Reactor Builder release should I use?
NuclearCraft Reactor Builder NC-ReactorBuilder-1.12.2-1.0.2.jar targets 1.12.2. The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server. No extra mods listed for this file.
Where it goes
Is NuclearCraft Reactor Builder required on the client, server, or both?
The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server.
The source does not explicitly classify this release as client-only or server-only.
What else does NuclearCraft Reactor Builder NC-ReactorBuilder-1.12.2-1.0.2.jar need?
NC-ReactorBuilder-1.12.2-1.0.2.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
19 extra mods were pulled in by other dependencies. Indented rows show who needs each one. We only count dependency files that match this setup. A file for another loader does not fill the gap.
Before you install it
Add NuclearCraft Reactor Builder without breaking your instance.
Built for NuclearCraft Reactor Builder NC-ReactorBuilder-1.12.2-1.0.2.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use NC-ReactorBuilder-1.12.2-1.0.2.jar. It targets 1.12.2; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server.
- 04
Pick the file you checked
Use the “Get this file” button beside NC-ReactorBuilder-1.12.2-1.0.2.jar. It opens that exact file at the source.
About this project
What does NuclearCraft Reactor Builder add?

NuclearCraft Reactor Builder
This mod accepts NuclearCraft Reactor Designs and builds them for you, it accepts both NCPF & JSON.
Features:
- Works for Underhaul & Overhaul
- Automated Building & Destroying
- Automated filter setting for Fuel Cells/Vessels and Neutron Irradiators.
- Automated casing building
- Can automatically fix reactors after meltdowns.
- Can build reactors of any size.
- Hologram to show the build area
- 3D Render Preview + Layer Preview page
- Configurable casing (Glass / Solid / Edges)
- Required components page.
- Config for Speed / Energy Consumption.
- Highlights blocks which are blocking the builder
- Creative Reactor Builder
- Casing components: automatic neutron source/controller/port placement
- All addons supported in Thiz's reactor planner are supported
Supported Reactors:
- Underhaul SFR [NCPF Coming soon]
- Overhaul SFR
- Overhaul MSR [Coming soon]
- Overhaul Turbine
Supported Files:
- Thiz Reactor Planner: NCPF [WIP, Partially supported]
- Hellrage Reactor Planner: JSON
Planned Features:
- Rotating reactors
Modpacks:
Feel free to use this in as many packs as you wish!
How to use
Copy a NCPF/JSON file in your file explorer.
Click Paste File in the builder's gui
Put the required components in a chest or inventory placed above the builder
Give the builder some energy
Click Build Reactor in the builder's gui
Example setup:

Screenshots:

Project description from CurseForge.
Pick your setup
NuclearCraft Reactor Builder by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.12.2
2 loader buildsCheck the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
NuclearCraft Reactor Builder versions and loaders
NC-ReactorBuilder-1.12.2-1.1.0a.jar
13 Jun 2025
NC-ReactorBuilder-1.12.2-1.0.4b.jar
9 Apr 2023
NC-ReactorBuilder-1.12.2-1.0.4a.jar
8 Apr 2023
NC-ReactorBuilder-1.12.2-1.0.3g.jar
6 Apr 2023
NC-ReactorBuilder-1.12.2-1.0.2.jar
11 Apr 2021
NC-ReactorBuilder-1.12.2-1.0.1.jar
6 Dec 2020
NC-ReactorBuilder-1.12.2-1.0.0.jar
1 Dec 2020
Looking for an older file? The official CurseForge project page is in Resources.