Did you know that all nuclear reactor technology originated at Argonne National Laboratory? The Manhattan Project, in which the first fission chain reaction was sustained, started at the University of Chicago. The lab was then moved to the Chicago suburbs and became known as the Argonne National Laboratory, the first of it's kind in the United States. Argonne expanded to Argonne-West in Idaho to run reactor experiments away from the densely populated Chicago area. In 2005, the US Department of Energy merged Argonne-West with the Idaho National Energy and Environmental Laboratory to form the current Idaho National Laboratory.
All reactor technology that is used around the world originated at these sites or were designed by Argonne. The tree below shows the development of each generation of reactors. The base of the tree is CP-1, the world's first reactor developed as part of the Manhattan Project, below the bleachers at the unused football stadium at UChicago. Next came research reactors (the bottom left branch) and then pressurized water reactors and production reactors (bottom right branch). Production reactors were used to produce plutonium for weapons and pressurized water reactors were developed for use in submarines and later electricity production. Boiling water reactors (top left) were also developed for electricity production. And finally, fast reactors (top right) are the next generation of advanced reactors to be used for electricity production. They can actually consume nuclear waste as fuel!