[Rury]

A lot of research has been done on this, and the vast majority of mutations are neutral, and have no affect on an organism. That is not good, nor bad. Somewhere between 75 to 90 percent of our own DNA, is nonfunctional, and never used.

But in any case, increasing the mutation rate, does increase the chance of bad mutations of happening, since it increases any kind of mutations from happening.

[klipt]

Radiation causes mutations.

Exposing yourself to excessive radiation is much more likely to cause cancer than superpowers. (In addition to a bunch of neutral mutations that do neither.)