The guy is spewing utter crap.
Nuclear power plants are hard targets.
A terrorist will seek an easy target because he is going to give up his life in the process of blowing up that target.
He wants the odds on his side that he will succeed.
A terrorist that tries to take out a nuclear plant has the odds staked against him by a huge margin.
Yes you can drive on to the parking lot at most of the plants but still leaves you far away from the reactor or the real target the control room.
if you google Calvert Cliff you can see pictures of the plant. You will see that the reactor building is a cylindrical building of reinforced concrete designed to withstand a direct hit by a 727 airliner.
A terrorist with a RPG is not going to do any harm to that reactor.
Perhaps the reporter mistook the cooling towers for the reactor.
Or perhaps he is lying.
I certainly hope his report is not accurate.