CurseForge · Minecraft mod
Criticality
Adds reactors to the game
Quick answer
Which Criticality release should I use?
criticality-neoforge-1.21.1-0.4.0.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Criticality required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does criticality-neoforge-1.21.1-0.4.0.jar need?
criticality-neoforge-1.21.1-0.4.0.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.
This file does not list any required or optional mods.
Before you install it
Add Criticality without breaking your instance.
Built for criticality-neoforge-1.21.1-0.4.0.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use criticality-neoforge-1.21.1-0.4.0.jar. It targets 1.21.1 with NeoForge; 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 this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside criticality-neoforge-1.21.1-0.4.0.jar. It opens that exact file at the source.
About this project
What does Criticality add?

Criticality adds multiblock nuclear reactors modelled on the real designs, and the steam plant to run them.
13 reactors, each its own building and its own way of failing: Graphite Pile, TRIGA, PWR, BWR, CANDU, RBMK, Magnox, AGR, HTGR, Microreactor, Molten Salt Reactor, LFTR and a Sodium Fast Breeder.
A real simulation every tick: neutron kinetics, xenon, decay heat, temperatures, pressure, boiling and burnup. Control rods, AUTO regulator, SCRAM, and trips you can switch off at your own risk.
Steam plant: boilers, steam engines, a multiblock turbine you build blade by blade, cooling towers, pipes and cables.
Inspection Goggles: look at any pipe, machine or reactor block to see what flows through it and what it is doing.
Operator's Manual with a step-by-step start-up for every reactor, and a **Structure Projector** that shows every blueprint as a hologram.
Meltdowns: steam explosions, hydrogen burns, corium and mushroom clouds that leave irradiated ground. World damage can be turned off for servers.
Mekanism support: This is the core feature of the mod, as all of the energy can be converted to mekanism energy.
The mod is in a very early state, i dont know if i will update it or not, it depends on how the mod will sit with downloads
Forge 1.20.1, NeoForge 1.20.1 and NeoForge 1.21.1. No other mods required.
Project description from CurseForge.
Pick your setup
Criticality by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.20.1
2 loader buildsCheck the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Criticality versions and loaders
criticality-neoforge-1.21.1-0.4.0.jar
15 Nov 2026
criticality-neoforge-1.20.1-0.4.0.jar
15 Nov 2026
criticality-forge-1.20.1-0.4.0.jar
15 Nov 2026
criticality-forge-1.20.1-0.3.0.jar
7 Oct 2026
criticality-neoforge-1.20.1-0.3.0.jar
7 Oct 2026
criticality-neoforge-1.21.1-0.3.0.jar
7 Oct 2026
Looking for an older file? The official CurseForge project page is in Resources.