That's probably based upon older reactor designs like everything in the nuclear industry, since regulation had made progress slow-going.

Newer designs, and some others, burn spent fuel. Out of the 3 major nuclear reactor incidents, all were old reactor designs. There are new ones that also cannot meltdown in the common understanding of the term.

Don't forget coal mining releases nuclear radiation, since you are unearthing radioactive minerals. So much so, that you are exposed to more radiation in the vicinity of a coal plant than a nuclear reactor.