The Manhattan Project: Making the Atomic Bomb

Part III: The Manhattan Engineer District

Time for Decisions

The Military Policy Committee met on November 12, 1942, and its decisions were ratified by the S-1 Executive Committee two days later. The Military Policy Committee, acting on Groves' and Conant's recommendations, cancelled the centrifuge project. Gaseous diffusion, the pile, and the electromagnetic method were to proceed directly to full-scale, eliminating the pilot plant stage. The S-1 Executive Committee approved these recommendations and agreed that the gaseous diffusion facility was of lower priority than either the pile or the electromagnetic plant but ahead of a second pile. The scientific committee also asked DuPont to look into methods for increasing American supplies of heavy water in case it was needed to serve as a moderator for one of the new piles.