The Tennessee Valley Authority announced today that they were considering upgrading some of their facilities in wake of the Fukushima nuclear disaster. Three of the TVA's six nuclear reactors have the same design as the Japanese plants. The big changes appear to be reducing the amount of spent fuel kept in pools and adding backup generation.

But it's the little changes that the TVA is considering that are most interesting because of the problem set that they imply. The Times lays them out: "...improving electrical switchyards to make them more resistant to earthquakes, adding small generators to recharge cellphone batteries and keep the lights on, and reinforcing the pipes that provide cooling water to spent fuel pools."

Think about the problems they're trying to solve with these changes. Any part of the grid could get knocked and cause trouble. That's an appropriately high-tech problem. But look at the others: cellphone charging, lights and leaky pipes. In some other setting, problems with these things would be mildly important. At a nuclear power plant, they could make responding to a disaster difficult or help cause one. And it's these small safety problems that make current-gen nuclear power difficult. Every single little thing has to work just right.