Well let's put it this way:   There have been zillions of epidemiological studies on the subject and they're all over the place, but mostly they don't show much.  One I heard about suggested it was more dangerous to work in an office than in a nuclear plant.   (In a nuclear plant you're monitored.

If people did zillions of epidemiological studies of coal plants - and they don't - one would find cancers as well.

If we did studies of people who work with silicon, we might find something there.

I don't understand why only nuclear energy gets an "assumption" of cancer.    I'll bet that the number of cancers of the lung resulting from air pollution number in the millions each year.