 Walter Henry Zinn designed and built several new reactors, including one that produced sufficient electricity to illuminate four what?
Walter Zinn: Walter Henry Zinn (December 10, 1906 – February 14, 2000) was a nuclear physicist who was the first director of the Argonne National Laboratory from 1946 to 1956. Walter Zinn:  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. Experimental Breeder Reactor I: Experimental Breeder Reactor I (EBR-I) is a decommissioned research reactor and U.S. National Historic Landmark located in the desert about 18 mi southeast of Arco, Idaho. Experimental Breeder Reactor I:  At 1:50 p.m. on December 20, 1951, it became one of the world's first electricity-generating nuclear power plants when it produced sufficient electricity to illuminate four 200-watt light bulbs. Electricity had earlier been generated by a nuclear reactor on September 3, 1948 at the X-10 Graphite Reactor in Oak Ridge, Tennessee.
200-watt light bulbs.