 At Argonne he designed and built several new reactors, including Experimental Breeder Reactor I, the first nuclear reactor to produce electric power, which went live on December 20, 1951.Walter Henry Zinn was born in Berlin (now Kitchener), Ontario, on December 10, 1906, the son of John Zinn, who worked in a tire factory, and Maria Anna Stoskopf.He had an older brother, Albert, who also became a factory worker.