This mod reworks the radiation (Rads) system of Nukacraft to be more authentic to the Fallout games.

Content:

Accrued Rads now remove a percentage of maximum HP. Each Rad removes 0.1% Max HP. Gaining a total of 1000 Rads will result in death due to radiation poisoning. Lost Max HP is visualised on Nukacraft's Fallout-style UI.

Consumable Items have had their Rad values updated to reflect their values in Fallout 4/76.

Two new gamerules have been added.

• keepRads (true/false) (default: false) 
  Similar to keepInventory, keepRads when enabled causes players to keep accrued Rads on death.
  
  
• maxRespawnRads (int: {0,999}) (default: 750)
  This is the upper limit to the amount of Rads a player can respawn with if keepRads = true. If a player dies with more Rads than the value of maxRespawnRads, then upon respawning their total Rads will be lowered back down to the limit. This is based on the mechanics of Fallout 76.

Mekanism Support:

There is also support for Mekanism's radiation. The negative effects of radiation exposure of screen tinting, loss of hunger and constant damge has been disabled for players, simply increasing the Rad count. Shielding and the Hazmat suit will still reduce the Rads gained by this means. Using the dosimeter on a player will show their Rad count instead of their Sv dose. Non-player entities interactions with Mekanism's radiation have not been affected.

For extended integration of Mekanism and Nukacraft, check out MekaNuka.
https://www.curseforge.com/minecraft/mc-mods/mekanuka