Abstract
On the basis of Manhattan Engineer District documents, a little known Naval Research Laboratory report of 1946, and other sources, I construct a more complete history of the liquid-thermal-diffusion method of uranium enrichment during World War II than is presented in official histories of the Manhattan Project. This method was developed by Philip Abelson (1913–2004) and put into operation at the rapidly-constructed S-50 plant at Oak Ridge, Tennessee, which was responsible for the first stage of uranium enrichment, from 0.72% to 0.85% U-235, producing nearly 45,000 pounds of enriched U-235 by July 1945 at a cost of just under $20 million. I review the history, design, politics, construction, and operation of the S-50 liquid-thermal-diffusion plant.
This is a preview of subscription content, access via your institution.





Notes
Wells N. Thompson was chief engineer of the H.K. Ferguson Company, while William I. Thompson of the Standard Oil Development Company was a member of the various Lewis committees.
The identity of “Meier” in Briggs’s letter is not clear. If this is a misspelling, he may be referring to physicist R.C. Meyer of the Carnegie Institution.
References
Richard G. Hewlett and Oscar E. Anderson, Jr., A History of the United States Atomic Energy Commission. Vol. I. The New World, 1939/1946 (University Park, Penn.: The Pennsylvania State University Press, 1962), p 173.
Ibid., pp. 297, 624.
H.D. Smyth, A General Account of the Development of Methods of Using Atomic Energy for Military Purposes Under the Auspices of the United States Government 1940-1945 (Washington, D.C.: U.S. Government Printing Office, 1945), §11.37-11.40, p. 147; reprinted as Henry DeWolf Smyth, Atomic Energy for Military Purposes: The Official Report on the Development of the Atomic Bomb under the Auspices of the United States Government, 1940-1945 (Princeton: Princeton University Press, 1945), §11.37-11.40, pp. 202-203.
Vincent C. Jones, United States Army in World War II. Special Studies. Manhattan: The Army and the Atomic Bomb (Washington, D.C.: Center of Military History, United States Army, 1988), Chapter VIII, pp. 172-183.
U.S. National Archives and Records Administration, Microfilm A1218, Reel 10, includes Manhattan District History (hereafter MDH), Book VI, “Liquid Thermal Diffusion (S-50) Project.” This consists of a Foreword dated May 21, 1947, a 17-page summary, and a number of sections and appendices describing topics such as the underlying theory, contractor selection, NRL involvement, a description of the plant itself, operations, organization and personnel, maps and charts, photographs, a list of contractors, contract letters, a bibliography, and a glossary.
John Abelson and Philip H. Abelson, Uncle Phil and the Atomic Bomb (Greenwood Village, Colorado: Roberts and Company, 2008).
Joseph-James Ahern, “‘We had the hose turned on us!’: Ross Gunn and the Naval Research Laboratory’s early research into nuclear propulsion, 1939-1946,” Historical Studies in the Physical and Biological Sciences 33, Part 2 (2003), 217-236.
Peter Vogel, The Last Wave from Port Chicago (2001, 2009). Appendix A. Document transcriptions: The liquid thermal diffusion uranium isotope separation method, website <http://www.petervogel.us/lastwave/chapterA.htm>.
Philip Abelson, Ross Gunn, and A. H. Van Keuren, “Progress Report on Liquid Thermal Diffusion Research,” NRL report 0-1977, January 4, 1943.
Philip H. Abelson, Nathan Rosen, and John I. Hoover, ed., “Liquid Thermal Diffusion,” NRL report TID-5229, September 10, 1946. This report also goes under the identifier NRL 0-2982; website <http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=4311423>.
Philip Abelson, “Cleavage of the Uranium Nucleus,” The Physical Review 55 (1939), 418.
Philip Abelson, “An Investigation of the Products of the Disintegration of Uranium by Neutrons,” Phys. Rev. 56 (1939), 1-9.
Abelson and Abelson, Uncle Phil (ref. 6), pp. 76-78.
Edwin McMillan and Philip Hauge Abelson, “Radioactive Element 93,” Phys. Rev. 57 (1940), 1185-1186; G.T. Seaborg, E.M. McMillan, J.W. Kennedy, and A.C. Wahl, “Radioactive Element 94 from Deuterons on Uranium,” Phys. Rev. 69 (1946), 366-367.
Ahern, “Ross Gunn” (ref. 7), p. 222; Harold C. Urey, “Separation of Isotopes,” Reports on Progress in Physics 6 (1939), 48-77.
Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 6.
D. Enskog, “Über eine Verallgemeinerung der zweiten Maxwellschen Theorie der Gase,” Physikalische Zeitschrift 12 (1911), 56-60, idem, “Bemerkungen zu einer Fundamentalgleichung in der kinetischen Gastheorie,” ibid., 533-539; S. Chapman, “On the law of distribution of Molecular Velocities, and on the Theory of Viscosity and Thermal Conduction, in a Non-uniform Simple Monatomic Gas,” Philosophical Transactions of the Royal Society of London [A] 216 (1916), 279-348.
S. Chapman and F.W. Dootson, “A Note on Thermal Diffusion,” The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 33 (1917), 248-253.
Klaus Clusius and Gerhard Dickel, “Neues Verfahren zur Gasentmischung und Isotopentrennung,” Die Naturwissenschaften 26 (1938), 546.
Arthur Bramley and A. Keith Brewer, “A Thermal Method for the Separation of Isotopes,” The Journal of Chemical Physics 7 (1939), 553-554.
Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 5.
R. Clark Jones and W.H. Furry, “The Separation of Isotopes by Thermal Diffusion,” Reviews of Modern Physics 18 (1946), 151-224.
K. Fuchs and R. Peierls, “Separation of Isotopes” [DTA Report MS12A, early 1941], in R.H. Dalitz and Sir Rudolf Peierls, ed., Selected Scientific Papers of Sir Rudolf Peierls With Commentary (Singapore, New Jersey, London, Hong Kong: World Scientific and London: Imperial College Press, 1997), pp. 303-320.
Abelson and Abelson, Uncle Phil (ref. 6), p. 92.
Ibid., p. 96.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), p. 3.
Abelson and Abelson, Uncle Phil (ref. 6), p. 93.
Kistiakowsky to Briggs, September 9, 1940, in Vogel, Document transcriptions (ref. 8), pp. 5-6.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), p. 3. Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 22.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), p. 4; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 22.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), p. 4.
B. Cameron Reed, “Arthur Compton’s 1941 Report on explosive fission of U-235: A look at the physics,” American Journal of Physics 75 (2007), 1065-1072.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), p. 4.
Hewlett and Anderson, New World (ref. 1), p. 169.
Ahern, “Ross Gunn” (ref. 7), pp. 224 -225.
G. Pascal Zachary, “Vannevar Bush Backs the Bomb,” The Bulletin of the Atomic Scientists 48 (December 1992), 24-31, on 29.
Smyth, Atomic Energy (ref. 3), §5.17, p. 57; 81.
Hewlett and Anderson, New World (ref. 1), pp. 169; Extract of a report of Urey, July 27, 1942, in Vogel, Document transcriptions (ref. 8), p. 6.
Hewlett and Anderson, New World (ref. 1), pp. 169, 679, n. 68; Bush to Purnell, December 31, 1942, in Vogel, Document transcriptions (ref. 8), pp. 8-9; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 23.
Ahern, “Ross Gunn” (ref. 7), p. 223; Jones, United States Army (ref. 4), p. 173; Abelson and Abelson, Uncle Phil (ref. 6), p. 97; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 23.
Hewlett and Anderson, New World (ref. 1), p. 169; Jones, United States Army (ref. 4), p. 174.
Jones, United States Army (ref. 4), p. 174; Hewlett and Anderson, New World (ref. 1), p. 169; Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), pp. 5-9.
Lewis to Conant, December 12, 1942, in Vogel, Document transcriptions (ref. 8), pp. 6-7, on 7.
Conant to Lewis, December 14, 1942, ibid., p. 7.
Bush to Purnell, December 31, 1942, ibid., pp. 8-9.
Letter of Special Subcommittee of the S-1 Executive Committee, January 23, 1943, ibid., pp. 10-15.
W.I. Thompson, “Analysis of Separation Data From Liquid Thermal Diffusion Experiments,” in Vogel, Document transcriptions (ref. 8), pp. 41-45.
Murphree to Briggs, January 25, 1943, and Urey to Briggs, January 28, 1943, ibid., pp. 17-19.
Briggs to Conant, January 30, 1943, ibid., pp. 19-21.
Hewlett and Anderson, New World (ref. 1), p. 171.
Murphree and Urey to Briggs, February 19, 1943, in Vogel, Document transcriptions (ref. 8), pp. 22-25.
Briggs to Conant, February 23, 1943, ibid., p. 21.
Conant to Groves, February 24, 1943, ibid., pp. 25-26.
Jones, United States Army (ref. 4), p. 175.
Abelson, Gunn, and Van Keuren, “Progress Report” (ref. 9), pp. 5-9.
Ahern, “Ross Gunn” (ref. 7), p. 226; Abelson and Abelson, Uncle Phil (ref. 6), p. 104.
Groves to Conant, July 10, 1943, in Vogel, Document transcriptions (ref. 8), p. 27.
Conant to Purnell, July 10, 1943, ibid., pp. 27-28.
Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), pp. 23-24.
Quoted in Abelson and Abelson, Uncle Phil (ref. 6), pp. 103-104.
Quoted in Ahern, “Ross Gunn” (ref. 7), p. 226.
Ibid., pp. 226-228; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), pp. 24-25.
Hewlett and Anderson, New World (ref. 1), p. 172; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 62; Lewis, Murphree, and Tolman to Groves, June 3, 1944, in Vogel, Document transcriptions (ref. 8), pp. 35-37, on pp. 35-36.
Abelson, Rosen, and Hoover “Liquid Thermal Diffusion” (ref. 10), pp. 36, 39, 72.
Ibid., pp. 78-79.
Abelson and Abelson, Uncle Phil, (ref. 6), pp. 106-108; Hewlett and Anderson, New World (ref. 1), p. 168; Richard Rhodes, The Making of the Atomic Bomb (New York, Simon and Schuster, 1986), pp. 551-552.
Conant to Purnell, March 4, 1944, in Vogel, Document transcriptions (ref. 8), p. 31.
Purnell to Conant, March 17, 1944, ibid., p. 32.
Ruth E. Jenkins (on behalf of Conant) to Oppenheimer, March 20, 1944, ibid., pp. 32-33.
Jones, United States Army (ref. 4), p. 176.
Lewis, Murphree, and Tolman to Groves, June 3, 1944, in Vogel, Document transcriptions (ref. 8), pp. 35-37.
Jones, United States Army (ref. 4), p. 177.
Abelson and Abelson, Uncle Phil (ref. 6), p. 110; MDH (ref. 5), pp. 3.6, D1-D3; Jones, United States Army (ref. 4), p. 178; Hewlett and Anderson, New World (ref. 1), p. 172.
Robert S. Norris, Racing for the Bomb: General Leslie R. Groves, the Manhattan Project’s Indispensable Man (South Royalton, Vermont: Steerforth Press, 2002), pp. 151, 365.
MDH (ref. 5), p. 4.1.
Ibid., pp. S6, 3.7, 3.18.
Ibid., pp. S3-4, 3.18; Abelson and Abelson, Uncle Phil (ref. 6), p. 111.
Ahern, “Ross Gunn” (ref. 7), pp. 229-230; Abelson and Abelson, Uncle Phil (ref. 6), p. 112. For a list of the injured, see Joseph-James Ahern, “We had the hose turned on us!” Ross Gunn and The Naval Research Laboratory’s Early Research into Nuclear Propulsion, 1939-1946,” International Journal of Naval History 2 (April 2003), n. 21; website <http://ijnhonline.org/volume2_number1_Apr_03/article_ahern_gunn_apr03.htm>.
Arnold Kramish, The Griffin (Boston: Houghton Mifflin Company, 1986).
MDH (ref. 5), pp. S12, 5.3. Abelson Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 26.
Ahern, “Ross Gunn” (ref. 7), p. 230.
MDH (ref. 5), pp. 4.2-4.4, 5.17-5.18; Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), pp. 59-60.
MDH (ref. 5), pp. S17, E2-3.
Ibid., pp. 3.18, 5.4.
Ibid., pp. 2.14, 3.10-3.11.
Ibid., pp. S7-8, 3.3, 3.19, 3.10-3.17, D6.
Ibid., pp. S17, 5.1.
Ibid., pp. 5.2, D3-5.
Ibid., pp. 5.4, S17; Hewlett and Anderson, New World (ref. 1), p. 300; Jones, United States Army (ref. 4), p. 182.
MDH (ref. 5), “Top Secret Supplement.”
Ibid., p. 1.2; Ahern, “Ross Gunn” (ref. 7), p. 234.
MDH (ref. 5), pp. 5.27-5.28.
Abelson, Rosen, and Hoover, “Liquid Thermal Diffusion” (ref. 10), p. 26; Ahern, “Ross Gunn” (ref. 7), p. 231.
“ORAU TEAM Dose Reconstruction Project for NIOSH,” website <http://www.cdc.gov/niosh/ocas/pdfs/tbd/s50-r0.pdf>, Sections 2.1 and 2.2.
Conant to Briggs, April 20, 1944, in Vogel, Document transcriptions (ref. 8), p. 33.
Conant to Bush, May 6, 1944, ibid., pp. 33-34; Abelson and Abelson, Uncle Phil (ref. 6), pp. 109-110.
Edward R. Landa and John R. Nimmo, “The Life and Scientific Contributions of Lyman J. Briggs,” Soil Science Society of America Journal 67 (3) (May-June 2003), 681-693, on 688, 691.
Conant to Briggs, September 15, 1944, in Vogel, Document transcriptions (ref. 8), pp. 38-39.
Briggs to Conant, September 21, 1944, ibid., pp. 39-40.
Acknowledgements
I am grateful to John Abelson and Joseph-James Ahern for providing copies of various documents to me, and for a number of stimulating e-mail exchanges. I thank Ray Smith for supplying the photograph in figure 4 to me, Cindy Kelly of the Atomic Heritage Foundation for permission to reproduce the photograph of Philip Abelson in figure 1, and Jeremy Bernstein for alerting me to the Fuchs-Peierls thermal-diffusion memorandum. I am indebted to Susan Tackett and Delores Branson at the Office of Scientific and Technical Information for their efficient help in making Abelson’s 1946 NRL report available to me. Finally, I thank Roger H. Stuewer for his careful and helpful editorial work on my paper.
Author information
Authors and Affiliations
Corresponding author
Additional information
B. Cameron Reed is Professor of Physics at Alma College in Alma, Michigan. His research interests include optical astronomy and the history of the Manhattan Project.
Rights and permissions
About this article
Cite this article
Cameron Reed, B. Liquid Thermal Diffusion during the Manhattan Project. Phys. Perspect. 13, 161–188 (2011). https://doi.org/10.1007/s00016-010-0039-0
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00016-010-0039-0
Keywords
- Philip H. Abelson
- Lyman J. Briggs
- Vannevar Bush
- Arthur H. Compton
- James B. Conant
- Leslie R. Groves
- Ross Gunn
- Merle A. Tuve
- Harold C. Urey
- Manhattan Project
- S-1 Committee
- H.K. Ferguson Co.
- S-50 plant
- liquid thermal diffusion
- uranium enrichment