Oral Histories

Philip Abelson first became involved in uranium enrichment while a graduate student at the University of California-Berkeley, working with cyclotrons under Ernest O. Lawrence. He explains how he came up with the idea that liquid thermal diffusion could enrich uranium-238 to U-235, how this process was implemented first at a factory at the Philadelphia Navy Yard and later at the S-50 Plant in Oak Ridge, and the important role the S-50 Plant played in the uranium enrichment process. He recalls his encounters with Lawrence, J. Robert Oppenheimer, William “Deak” Parsons, Edwin McMillan, Luis Alvarez, and other Manhattan Project leaders.

Dr. Philip Abelson was a physicist on the path to discovering fission when Otto Hahn and Lisa Meitner discovered this process first. Abelson worked at the Navy Research Laboratory in Philadelphia, where he designed pipes to enrich uranium. He discusses how he was also the first in the United States to manufacture large quantities of uranium hexafluoride. Abelson’s technology was reviewed by General Leslie R. Groves, Edward Teller, and J. Robert Oppenheimer. His research led to the rapid construction of the S-50 Plant in Oak Ridge, the liquid thermal diffusion plant. He recalls the challenges of designing pipes for uranium enrichment.

Ray Smith is the historian at the Y-12 National Security Complex. He provides an overview of the history of Oak Ridge, the uranium enrichment processes undertaken at the Y-12, K-25, and S-50 plants during the Manhattan Project, and how the Fat Man and Little Boy bombs worked. Smith talks about efforts to preserve Oak Ridge’s unique history.