The bad science behind expensive nuclear

Even if we ignore the mechanisms for nucleic acid repair and we assume that any level of radiation causes a risk of mutations, thus of cancer, proportional to it, the fact that the human bodies and their environments are intrinsically radioactive unavoidably creates a threshold effect for any additional radiation caused by human activities.

As long as the additional radiation remains smaller than the natural levels of radiation to which our bodies are exposed, from their internal content of radioactive potassium, radioactive carbon and radioactive calcium and from the ambient cosmic radiation, the additional radiation cannot produce observable effects, so there exists a threshold that cannot be lower than the natural radiation level.

The greatest danger from artificial sources of radiation comes from substances like radioactive iodine, which would be concentrated in a very small part of the body, instead of being diluted through the entire body, like the natural radioactive elements.