Kiwi A fire-up. Kiwi-A Prime is one of a series of atomic reactors for studying the feasibility of nuclear rocket propulsion, in Los Alamos, New Mexico. Developed by the Los Alamos Scientific Laboratory for the U.S. Atomic Energy Commission, the reactor underwent a highly successful full-power run on July 8, 1960, at Nevada Test Site in Jackass Flats, Nevada.