Inside a Nuclear Reactor

<b>Down the Rabbit Hole</b> Admiral Hyman Rickover standing on ladder which makes long descent into circular nuclear reactor shell at the Shippingport power facility. (Yale Joel/Time & Life Pictures/Getty Images)

<b>Reactor Face in 1952</b> Researchers work on an atomic reactor. (Al Fenn/Time & Life Pictures/Getty Images)

<b>Nuclear Energy on the Half-Shell</b> Two men look at the bottom half of the reactor-to-be at the Dounreay atomic power plant in Scotland, a steel ball 135 feet wide, made of welded plates, in 1956. (Charles Hewitt/Picture Post/Getty Images)

<b>On Top of It All</b> Men construct the top of the reactor at the Dounreay atomic power plant. The fissile plutonium core will be hung in the central hole. (Charles Hewitt/Picture Post/Getty Images)

<b>Bridge to the Atomic Age</b> A nuclear reactor is under construction near Mumbai, India in 1955. <a href="http://www.life.com/gallery/57831#index/0">See Life for the full Slideshow</a> (Dinodia Photos/Getty Images)