I have been on walk throughs where they confiscate your camera and/ film/memory card , develop it themselves and send you back the pictures that they deem okay for public release. I was also on a walk through where they confiscated your shoes afterward. (That was a suprise to the people who didn't read the fine print ).
A word to the wise, if you are ever going on a walk through of a nuclear plant, don't wear any "wrinkle free" pants. The micro fibers can set off the radiation detectors. That's always fun when you expect to go up and back in a day and don't take any extra clothes.