[raketenjagdpanzer]

Every area not hit by a nuke in any T2k timeline that is also serviced by a nuclear power plant is basically living on borrowed time. Spent nuclear fuel is still crazy hot. It has to be kept in a water-circulated cooling pool. You'll wind up with a mini-Chernobyl accident at every one; once the grid goes down and breakers trip, the plant will automatically respond and lower its output rate. If it falls far enough the whole plant will enter a low-power, then a shutdown state. While not bad for the plant this means that the power to the cooling pumps for the fuel will shut off. Diesel generators can keep the power going for a day or so. Once that's gone, depending on the state of the spent fuel you may have a day or as much as a week or two before the water covering the fuel boils off.

Then comes the fires, explosions, and fallout.

As Olefin said regardless of which faction you're aligned with, taking control of those facilities is priority one.