This German nuclear phase-out policy was originally the vision of former Chancellor Gerhard Schroeder, who just happened to get a lucrative position with Gazprom, the Russian natural gas company, immediately after leaving office. Schroeder secured a one billion Euro loan guarantee for Gazprom's German pipeline project just weeks before leaving office. That pipeline is going to be Germany's source of fuel for their electrical grid once the nuclear plants go offline.
It's not just the US government that's in bed with the fossil fuel giants...
The map linked by mtngirl indicates that there's a 2% chance over a 50 year period of having an earthquake that exceeds 0.2g of peak ground acceleration. That's less than half the strength of the Japan quake, which measured over 0.5g. So yes, there's some risk of an earthquake in East Tennessee, but all nuclear facilities are designed to withstand seismic events.
The Japanese quake was less than 100 miles from the Fukushima plant. If there were a similar quake on the New Madrid fault, we're much further away (about 300 miles from Memphis), which would reduce the impact considerably. According to every credible account, the tsunami was the real source of the problems at the Fukushima plant. The plant response to the quake itself was as designed, and if not for the massive flood of seawater onto the site, there would not have been any safety concern at all.
As for a dam failure generating flooding that has "about the same result as a tsunami," perhaps you ought to be focusing your attention on the dams instead of the nuclear plants. If we have floods of the magnitude you seem to be expecting, you'll have more pressing issues to worry about than a bit of radiation.