Do tell, I just did a simple Google re Hanford Nuclear Site and am still wondering how you got so close for this incredible photograph?! The photo looks like a sepia hand colored but upon further inspection it is color, what a great one, the use of color and a sepia feel, almost conveys a historical (sepia) and current reality (color gage) all the same time...bravo!
All the lighting inside is either sodium vapor, which is why there is the color cast on this image, or florescent.
Anyone can visit Reactor B or the surrounding site via free tours run by the Dept of Energy. The site only tour is the only tour in which you can have a camera though.