Nuclear Radiation
Physics-driven radiation simulation for Minecraft. Real isotopes, real decay, real units. Radioactivity that behaves the way it does in the actual world - not a hand-wavy "rads" bar.
NOTE: This mod is in active development
If you've ever wanted Minecraft to take nuclear material seriously - where a dropped chunk of spent fuel is genuinely dangerous, where lead and concrete actually shield you, where iodine pills matter after exposure - this is that mod.
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What makes it different
Most radiation mods use a single abstract "rad" number. Nuclear Radiation models the real chain:
Source activity (Bq) → radiation field → shielding attenuation → biological dose (Sv)
Every step uses correct physics units and real-world behavior:
- Becquerel (Bq) - how active a source is (decays per second)
- Gray (Gy) - absorbed dose, used for shielding math
- Sievert (Sv) - the biological dose you accumulate (live rate + lifetime total)
Different radiation types behave differently, with proper quality factors:
- Alpha - deadly up close, stopped by almost anything (Q=20)
- Beta - moderate range (Q=1)
- Gamma / X-ray - penetrating, needs dense shielding (Q=1)
- Neutron - penetrating and nasty (Q≈10)
Features
Radiation that comes from real things
- Placed radioactive blocks emit into the world
- Dropped radioactive item stacks become hot spots on the ground
- Radioactive fluids irradiate their surroundings
- Chests and barrels full of hot material leak radiation (sealed = point source, no contamination spread)
- Chunks track soil / air / water contamination over time
Real decay
- Built-in isotopes: U-238, U-235, Pu-239, Cs-137, I-131, Sr-90, Y-90, Co-60, Cf-252
- Isotopes actually decay over time based on their real half-lives
- Decay chains with daughter products (e.g. Pu-239 → U-235, Sr-90 → Y-90)
- Short-lived isotopes burn out; long-lived ones stay hot for the long haul
Shielding that works like shielding
- Stand behind stone, iron, gold, water, obsidian, or netherite and it actually blocks radiation
- Dense materials block more - proper Beer–Lambert attenuation, traced block-by-block between source and you
- Different materials block X-ray and neutron radiation by different amounts
- Armor protects you - full iron/gold/netherite sets reduce incoming dose, configurable per radiation type
Exposure that's more than standing near it
- External dose from the radiation field around you
- Inventory dose - carrying a hot item in your hotbar, offhand, or pockets exposes you; armor slots shield more
- Internal dose from ingested or inhaled isotopes - and it stays in you
- Background radiation per dimension and per biome
Tools
- Geiger Counter - reads live activity (Bq) in the world; clicks faster the hotter it gets
- Dosimeter - your personal dose readout: total Sv, current Sv/h, and a breakdown of external / inventory / internal sources, with an on-screen HUD
Medicine
Exposure is survivable if you treat it:
- Iodine Pill - blocks I-131 from being taken up by your body
- Prussian Blue - flushes out Cesium-137
- Anti-Rad Injection - strong emergency purge
- Radaway - gradual cleanup over time
- Rad-Protection Potion - general resistance to incoming dose
One radiation system for all
- Unify radiation systems from different mods into single
- Mekanism - ✅
- NuclearCraft: Neohaul - ❔
- Hbm's Nuclear Tech: Neo Edition - ❔
- Industrial Upgrade - ❔
- Nuclear Science - ❔
- Alex's Caves - ❔
For map makers & modpack authors
- Creative Radiation Source block - place a fully tunable emitter, dial in Alpha / Beta / X-Ray / Neutron output in MBq
- Fully data-driven - assign radioactivity to any item, block, or fluid (yours or another mod's) via datapack JSON, tags, or per-stack data components
- Armor shielding values are datapack-driven too
- Deeply configurable: sim intervals, dose thresholds, recovery rates, contamination spread, background levels, and more
Recipe-viewer support
Full JEI and EMI integration with custom info pages:
- Isotope Stats - half-life, radiation mix, quality factors, decay products
- Radioactive Items - what's hot and how hot
- Decay Graph - visual decay chains
- Armor Radiation Protection - shielding values per armor piece
Planned
- Unified radiation framework - one radiation system to rule them all. Bridge the radiation mechanics from other mods (Mekanism and friends) into this single physics-based pipeline, so a radioactive item is equally dangerous no matter which mod made it - measured in the same Bq/Sv, blocked by the same shielding, treated by the same medicine. No more competing, incompatible "rad" bars.
Getting started
- Craft or grab a Geiger Counter and Dosimeter (Tools & Utilities creative tab)
- Go find something radioactive - the Geiger counter will tell you when you're close
- Watch your Dosimeter. Keep your total Sv down
- Put dense blocks (or distance) between you and the source
- Wear protective armor when working near hot material
- Keep iodine pills and Radaway on hand for when things go wrong
Requirements
- Minecraft 1.21.1
- NeoForge 21.1.230+
- Java 21
⚠️ Beta: This mod is in active development. Mechanics and balance may change between versions. Bug reports and feedback are welcome.
Performance
Built to run on real servers. The simulation runs on a dedicated background thread, uses a spatial radiation-field cache so cost scales with entities rather than entities × sources, has a hard radius cutoff on sources, and gates world/entity simulation on separate, configurable tick intervals. No off-thread world access.
Real units. Real decay. Real consequences.
License: MIT
