Childish question, Immunity from radiation?

Radiation does damage to living cells in two ways. The immediate damage is the tearing of cell walls so the fluid inside leaks out (cytoplasma). This is why intense radiation exposure causes the tissue to swell as the cells loose more of their fluid. The long term damage is done to the DNA which, if it happens just right, produces mutations which cause the cell to reproduce abnormally (cancer). Not sure about the details but some life forms seem to be more able to repair themselves by some cellular processes that mitigate the physical damage done to cells by ionizing radiation. This same mechanism may repair or avoid using DNA that has been damaged by radiation. roaches seem to be more tolerant of radiation than many other things.