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Cohen (Karl P.) papers
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  • Access to Collection
  • Publication Rights
  • Acquisition Information
  • Biographical
  • Preferred Citation
  • Scope and Contents

  • Language of Material: English
    Contributing Institution: Department of Special Collections and University Archives
    Title: Karl P. Cohen papers
    creator: Cohen, Karl P.
    source: Cohen, Karl P.
    Identifier/Call Number: M1798
    Physical Description: 30.42 Linear Feet (62 boxes: 50 manuscript boxes ; 1 record storage box ; 1 flat box)
    Date (inclusive): 1931-2010
    Abstract: Dr. Karl Paley Cohen was a physicist and advisor involving nuclear energy and reactor development who began his career making scientific advances in uranium production with the Manhattan Project at Columbia University in the 1940s. Working under Harold Urey, Cohen developed the now universal method of centrifugal isotope separation for enriching uranium. While the collection includes many declassified lab notebooks and journals from this time, it largely covers Cohen’s long period of service with General Electric as well as various consultancies, and includes reports, correspondence, notes, and other material related to nuclear electric power generation and its safety, economic viability, public policy and other concerns.

    Access to Collection

    Open for research. Note that material must be requested at least 36 hours in advance of intended use. Audiovisual materials are not available in original format, and must be reformatted to a digital use copy.

    Publication Rights

    While Special Collections is the owner of the physical and digital items, permission to examine collection materials is not an authorization to publish. These materials are made available for use in research, teaching, and private study. Any transmission or reproduction beyond that allowed by fair use requires permission from the owners of rights, heir(s) or assigns.

    Acquisition Information

    This collection was given by Karl Cohen to Stanford University, Special Collections in 2010.


    Karl Paley Cohen (1913-2012) was born in New York City. He studied chemistry at Columbia University from 1929 to 1936, followed by post-doctoral work in Paris (where he met his wife, Marthe-Hermance Cohen). Beginning in 1937 Cohen was research assistant to professor Harold Urey, who had earned the 1934 Nobel Prize in Chemistry for his work on isotopes. As the war escalated, Urey was named director of the Manhattan Project at Columbia, and Cohen was hired as head of the project’s Theoretical Division, with the responsibility for determining processes for U-235 (uranium) isotope separation. Subsequently, Cohen was deeply involved with perfecting the gaseous diffusion and centrifuge techniques for enrichment, and uranium sources and production would be a major focus of his career.
    In 1944 Dr. Cohen began working for Standard Oil, primarily studying the economics of the emerging nuclear energy industry. Following this, Cohen was a technical director for H.K. Ferguson's Atomic Energy Division, responsible for the construction of the Brookhaven nuclear reactor. By 1952, Cohen was a founder, vice president and operating manager of Walter Kidde Nuclear Laboratories, a privately-funded research facility formed to commercially develop nuclear power. The lab’s principal contract was with the Atomic Energy Commission for R&D on reactors, and established many industry standards, especially regarding slightly enriched uranium and water moderated reactor concepts.
    Cohen’s long association with General Electric began in 1956, at first as a consultant, then as a manager involved with advanced engineering, advanced products, breeder reactor development, and operational planning. In 1973 Cohen was appointed Chief Scientist of G.E.'s commercial nuclear department. After his retirement in 1978, Cohen consulted for companies such as G.E., Boeing, and Exxon, and organizations such as the Institute for Energy Research, Scientists and Engineers for Secure Energy and the Electric Power Research Institute. Cohen also continued to be active on committees, at conferences, and in more informal peer review of technology and policy papers. He also taught intermittently at Stanford during this time. Karl Cohen passed away after a long illness in 2012.
    Cohen holds several patents in nuclear reactor technology and isotope separation, having developed the now universally-used centrifuge method, and wrote the standard reference text "Isotope Separation" in 1945. He was elected to the National Academy of Engineering in 1967 and served as president of the American Nuclear Society for 1968-1969.

    Preferred Citation

    [identification of item], Karl Cohen papers (M1798). Dept. of Special Collections and University Archives, Stanford University Libraries, Stanford, Calif.

    Scope and Contents

    The papers of Karl Cohen include reports, papers, articles, notes, memoranda and correspondence, primarily related to nuclear power generation. The collection has been divided into fourteen series. Cohen's own work, with some declassified items dating from the 1930s and 40s, is contained for the most part in Series 1-4, although his student notebooks are in Series 9, and scientific reprints in Series 11. There are also media-specific series here for photographs, slides, and audiovisual material. The subject file series has been arranged alphabetically, and represent companies, organizations, countries, technical processes, and concerns (such as forecasting, economics, proliferation, and safety) which featured heavily in Cohen’s career.

    Subjects and Indexing Terms

    Nuclear energy.
    Nuclear reactors
    General Electric Company.
    Cohen, Karl P.
    Cohen, Karl P.
    Manhattan Project (U.S.)
    Urey, Harold Clayton