Nine reactors beat ZEEP into service

David Kramer’s article on nuclear developments in my native Canada (Physics Today, January 2021, page 23) was an enjoyable read. However, his assertion that the Zero Energy Experimental Pile (ZEEP) world’s second operating reactor after Enrico Fermi’s Chicago Pile-1 (CP-1) is erroneous; at least nine other stateside piles achieved criticality before ZEEP did so September 1945.Those US were CP-2 and CP-3 Argonne National Laboratory (March 1943 May 1944; first heavy-water pile); X-10 pilot-scale pile Oak Ridge (November 1943); 305 fuel-testing B, D, F plutonium production Hanford Site (1944 to early 1945); two small aqueous enriched-uranium devices, LOPO HYPO, Los Alamos (1944). outside achieve criticality. Section:ChooseTop of <<© 2021 American Institute Physics.