May only be immune to the effect of radiation, such as getting diseases.
May be limited on how much radiation their is.
The user may survive a nuclear explosion, but they may still feel some pain from the blast.
Ibara Naruse (Coppelion)
Aoi Fukasaku (Coppelion)
Taeko Nomura (Coppelion)
Utsuho Reiuji (Touhou Project)
Protagonist Characters (Fallout); via Rad Resistance & Rad Tolerance Perks
Ghouls (Fallout series)
Starfire (DC Comics)
Tamaraneans (DC Comics)
Red Star (DC Comics)
Mother of Champions (DC Comics)
Alexander Summers/Havok (Marvel Comics)
Sunspot (Marvel Comics)
Asgardians (Marvel Comics)
Blight (Batman Beyond)
NRG (Ben 10)
Time Lords (Doctor Who); immune to X-ray radiation
Daleks (Doctor Who)
Ted Sprague (Heroes)
Peter Petrelli (Heroes)
Homer Simpson (The Simpsons)
Ibara Naruse, Aoi Fukasaku and Taeko Nomura (Coppelion) have been genetically engineered to be impervious to radioactivity, making them able to enter any radiation zone with no harm.
Homer Simpson (The Simpsons) seems to be immune to nuclear radiation, as he simply shrugged off the radiation after emerging from a meltdown he caused, and even ate nuclear waste as a punishment with no ill effects.