Watched by Compton, Matthias, DuPont's Crawford Greenewalt, Leona Woods and Fermi, who inserted the first slug, the reactor was powered up beginning on 13 September 1944.
Under opsyn af Compton, Matthias, DuPont's Crawford Greenewalt, Leona Woods og Fermi, som indførte den første stav, blev reaktoren startet fra den 13. september 1944.