text: Hmmmm.... The first reactor was built in a squash court at UoM Chicago. It was a very VERY simple pile. After that... I'm betting the next one was in Hanford Washington.\n\nYou might be asking when was the first Nuclear Power Plant.... A construction built for the porpose of generating electricity for the masses.\n\nBest guess... That one the army Built that EXPLODED on them.\n\nJust a guess though.... You tried Wiki or even google yet?