I'm not sure they actually do. The highest figure nuclear proponents have come up with for radiation exposure from coal is about three times nuclear power plant

I'm not sure they actually do. The highest figure nuclear proponents have come up with for radiation exposure from coal is about three times nuclear power plants, if you only count the source of radiation exposure that coal and nuclear have in common, and that's for very polluting 1970s-era coal power plants of a type that probably wouldn't be allowed to operate today. Besides, coal power is dying out in the US anyway.