Today's earthquake in Virginia has forced the North Anna nuclear power plant offline. It is, as of this writing, operating on diesel backup power.
It appears at though the plant has been shut down safely and that the damage from the earthquake is not so severe as to pose a threat to public health. But the Virginia earthquake is a reminder that nuclear power plants face unpredictable conditions. As the disaster at Fukushima showed, when extreme conditions mix in unforeseen ways, or are combined with human error, the results can be disastrous.