diff --git a/data/mods/My_Sweet_Cataclysm/sweet_mutations.json b/data/mods/My_Sweet_Cataclysm/sweet_mutations.json
index cfecbb275fa74..c0ca6700d4037 100644
--- a/data/mods/My_Sweet_Cataclysm/sweet_mutations.json
+++ b/data/mods/My_Sweet_Cataclysm/sweet_mutations.json
@@ -42,6 +42,6 @@
     "allowed_category": [ "SUGAR" ],
     "no_cbm_on_bp": [ "TORSO", "HEAD", "EYES", "MOUTH", "ARM_L", "ARM_R", "HAND_L", "HAND_R", "LEG_L", "LEG_R", "FOOT_L", "FOOT_R" ],
     "armor": [ { "parts": "ALL", "cut": 10, "bash": 5 } ],
-    "flags": [ "NO_THIRST", "NO_DISEASE" ]
+    "flags": [ "NO_THIRST", "NO_DISEASE", "NO_RADIATION" ]
   }
 ]
diff --git a/doc/JSON_FLAGS.md b/doc/JSON_FLAGS.md
index fbab96e2a6353..714af7fe74781 100644
--- a/doc/JSON_FLAGS.md
+++ b/doc/JSON_FLAGS.md
@@ -1086,8 +1086,9 @@ Also see `monster_attacks.json` for more special attacks, for example, impale an
 
 - ```UNARMED_BONUS``` You get a bonus to unarmed bash and cut damage equal to unarmed_skill/2 up to 4.
 - ```NEED_ACTIVE_TO_MELEE``` This mutation gives bonus to unarmed melee only if it's active.
-- ```NO_DISEASE``` This mutation grants immunity to disease.
+- ```NO_DISEASE``` This mutation grants immunity to diseases.
 - ```NO_THIRST``` Your thirst is not modified by food or drinks.
+- ```NO_RADIATION``` This mutation grants immunity to radiations.
 
 
 ### Categories
diff --git a/src/character.cpp b/src/character.cpp
index 518c5b7b04a8d..2fefebdea9db5 100644
--- a/src/character.cpp
+++ b/src/character.cpp
@@ -5312,7 +5312,10 @@ void Character::set_rad( int new_rad )
 
 void Character::mod_rad( int mod )
 {
-    radiation += mod;
+    if( has_trait_flag( "NO_RADIATION" ) ) {
+        return;
+    }
+    set_rad( std::max( 0, get_rad() + mod ) );
 }
 
 int Character::get_stamina() const
diff --git a/src/player.cpp b/src/player.cpp
index eeb1bb9376c06..067d76e01bf1e 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -2832,7 +2832,7 @@ void player::regen( int rate_multiplier )
     }
 
     if( get_rad() > 0 ) {
-        set_rad( std::max( 0, get_rad() - roll_remainder( rate_multiplier / 50.0f ) ) );
+        mod_rad( -roll_remainder( rate_multiplier / 50.0f ) );
     }
 }