Washington, D.C., January 23, 2025 - Today, the National Security Archive publishes newly declassified information on a secret mid-1960s project in which a handful of young physicists at Lawrence Livermore Laboratory produced a design for a “credible nuclear weapon” based only on unclassified, open-source information and in just three years. One of the participants described the experiment as “truly a do-it-yourself project,” according to one of the recently declassified records. Begun in the spring of 1964, before China had conducted its first bomb test, the “Nth Country Experiment” concluded that a government with nuclear-weapons aspirations and limited resources could develop a “credible” weapon.
This new Electronic Briefing Book includes the relatively limited declassified literature on the project, including the 1967 “Summary Report on the Nth Country Experiment,” a document first released to the National Security Archive in the 1990s and that was the subject of an Archive press release in 2003. Today’s posting also includes a recently declassified, if massively redacted, Livermore report on “Postshot Activities of the Nth Country Experiment” that summarized classified briefings that two of the participants in the Experiment gave around the country to U.S. government officials. Also included is a State Department internal announcement of a forthcoming briefing on the “Nth Country Experiment” noting that “three young PhD physicists, working part-time, succeeded in achieving a workable nuclear weapons design in a period of about three years.”
To begin the Experiment, Livermore Laboratory selected two recent PhDs, David N. Pipkorn (University of Illinois) and David A. Dobson (University of California, Berkeley). When Pipkorn left the Experiment for full-time work at Livermore, Robert W. Selden (University of Wisconsin) joined the project. The Experiment lasted longer than the one year envisaged, not concluding until the spring of 1967, when Dobson and Selden were ready to stage a hypothetical test for their design of a plutonium implosion weapon. During the months after the “test,” Dobson and Selden were on the road briefing staff at agencies and laboratories, including Los Alamos, the Central Intelligence Agency, the Atomic Energy Commission, and the State Department. The briefers made their presentation in the form of a nightly news report, Huntley-Brinkley style.