Make sure that what happened to the nuclear reactors in japan does not happen here.

The loss of electric power to a nuclear power plant results
in the water not being replaced in the reactor nor in the
storage pool that contains spent rods.
This would cause a meltdown like Japan had.
In the event of terrorists using a atomic bomb to cause a
EM pulse that knocks out the power grid, there would be
no portable electric generators working unless some had
been stored in hardened sites near the power plants.
Another thing needed would be to have large water
storage tanks to be used without the need for electric pumps,
but only gravity to pass water to the reactor and storage
pool at the plant.
This would give the operators the time they would need to
lower all the graphite rods into the reactor.