Here the Credits:

Guide Book

The Guide book you will get when joining a new world
When interacting on it with any Machines of the Addon, it will say a guide on how to use it.
Which is why I only will give a small Description  of Items and Blocks
Or just sneak and interact so it explains the Radiation System

Examples:

Ores!

This addon adds 7 New ores! [The names of them are in the Spoiler]

Spoiler Ores

Strontium

The only not Radioactive Ore in this addon! It protects the player against Radiation

Berkelium

The Least Radioactive Ore in the Addon

Thorium

Not that radioactive compared to the other ores
 

Uranium

It's the between of the Radioactive elements

Radium

It's an Alloy out of Thorium and Uranium

Neptunium

Neptunium is one of the more Radioactive Ores and has a lot of uses

Plutonium

Plutonium is the most Radioactive Element

Items

Gaiger Counter

The first item is a Gaiger Counter, when interacted will tell you the amount of Radiation you have
 

Documentary Pieces

4 In total, those are only found in a structure and only has a bit of lore in them

Disk "Radioactive Disaster"

This Disk is found in the form of Fragments and also has lore in it
 

Potion of cure

This Potion is made out of Radium and will cure anything

Radioactive Core

Radioactive Core is used for Replacment for Crafting and as a power in some machines

Machines

Radioactive Container

The Radioactive Container can store an unlimited amount of Radioactive Elements/things

Pipes

R.A.M, Gas pipes and Heat Pipes are the main Pipes in this Addon

Heat Exchanger 

This is the Main Generator in this addon. It is compatible with RF from Advanced Machinery

Heat Storage and Destroyer

Those are fairly simple, the one Destroys Heat and the Other Stores it

Element Compressor

It will make nuggets to Ingots and Ingots to Blocks

Radioactive Compressor

Has a chance of turning stone/Deepslate to Radioactive Ores

Radioactive  Converter

This Machine Turns Elements into other Elements

Radioactive Storage

Pretty self explaining, ain't it? 

Gas Mixer

It will Mix Gasses together to create new things

Hydrogen, Fluorine, Chlorine, Helium and Oyxgen Extractor 

They Extract the Gasses out of the air

Radiation Spliter

Will Split Radiation with R.A.M Pipes from the side

Structure

The Only Structure is an abandoned Laboratory that spawns below Y = 0

And that is about it!
This Addon is Compatible with the Following: