Let me start with a couple links in today's episode of Security Theater.
Some commentary by Bruce Schneier
http://www.schneier.com/blog/archives/2007/04/how_australian.htmland the video linked by Bruce Schneier:
http://youtube.com/watch?v=McB9tsabPn0
Watch the video of how the Australian authorities react when someone -- dressed either as an American or Arab tourist -- films the Sydney Harbor Bridge and a nuclear reactor.
The synopsis: The Arab is intercepted within three minutes both times, while the U.S. tourist is given instructions on how to get inside the nuclear facility.
Moral for terrorists: dress like an American.
By the way, Lucas Heights is a research reactor. It produces medical isotopes and performs research, and doesn't produce power.