DuPont engineer George Graves had deviated from the Metallurgical Laboratory's original design in which the reactor had 1,500 tubes arranged in a circle, and had added an additional 504 tubes to fill in the corners.
Heldigvis havde DuPont ingeniøren George Graves afveget fra metallaboratoriets oprindelige tegning, hvor reaktoren havde 1.500 rør placeret i en cirkel, og havde tilføjet yderligere 504 rør for at udfylde hjørnerne.