The characteristic feature of a karst is the likelihood  of caves and caverns. It is not that one cannot build on it, but it is prudent to see if there is a big cavern beneath your building site, especially if it is a nuclear reactor. If you have solid limestone all the way down to shale or granite you would be good to go. But if there is a big cavern or water filled void 500 feet down, not so much. And I was referring to Germany, but the same kind of geology in Florida gives rise to sinkholes, which would also be highly undesirable as a feature under a nuclear reactor.

"It is not necessary to have hope in order to persevere."