[pessimizer]

>The ash is more radioactive than most nuclear waste is and there's a whole lot more of it to contain.

The question is if it's safer to be next to a nuclear meltdown or a burning coal plant, not whether portions of the waste of both plants during normal operations are more or less radioactive than each other.

[legitsource]

It's not a burning coal plant that's the problem. A tsunami would spread the ash from the coal plant everywhere.

Heavy metals from the ash would be a lot more hazardous in the short term than the radiation unless you were standing on top of the reactor.