Radiation damage in Warframe is a secondary elemental damage type. It is caused by mixing two primary element damage types. By mixing the primary damage types of Electricity and Heat, we can cause radiation damage. Radiation damage is very effective against Alloy Armor and is the current best damage to do while hunting Eidolons. When enemies are affected by Radiation damage, they will become confused. This will last for 12 seconds and will cause the unit to attack its own faction and member of that faction to attack back. Affected units will also cause 100 percent extra damage, which will increase by 50 percent with each additional proc of the confused status. This will max out at 550 percent, and each proc has its own duration, with further procs having no effect on the duration of previous procs. To complete the Reactor Challenge, you need to kill 150 enemies with Radiation Damage. How To Do Radiation Damage To cause Radiation damage, you need to mix Heat and Electricity mods in your weapon build. Mixing these two damage types will cause your primary, secondary or melee weapon to do Radiation damage. As you can see in the image above, the Electricity and Heat mods interact to cause Radiation damage. There are also some weapons in the game that will do innate Radiation damage. While it is easier to simply use mods to cause Radiation damage with any weapon you wish, it can be helpful to know which weapons in the game do specific damage types. As an example, by using an Electricity and a Heat mod on a weapon that already does Radiation damage, you will greatly increase the amount of Radiation damage it does. Arca Plasmor (primary)Battacor (primary)Mutalist Quanta (primary)Phantasma (primary)Secura Penta (primary)Cycron (secondary)Detron (secondary)Mara Detron (secondary)Nukor (secondary)Ocucor (secondary)Secura Dual Cestra (secondary)Staticor (secondary)Dark Dagger (melee)Dark Split-Sword (melee)Dark Sword (melee) Mirage's Prism attack, Nova's Anitmatter Drop, and Oberon's Hallowed Ground abilities all do Radiation damage as well. You should have no problem quickly wrapping up this challenge.