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National Museum of Nuclear Science & History

Saving Seaborg’s Plutonium

The plutonium speck. Image courtesy Eric Norman/U.C. Berkeley

In 2012, Berkeley health physicist Phil Broughton stopped by the office of the Atomic Heritage Foundation and relayed some exciting news: he had discovered a tiny plutonium sample at Berkeley, which he believed to be one of Seaborg’s first samples. In 1942, Chicago chemists Burris Cunningham and Lewis Werner purified and extracted plutonium from uranium salts. The sample at 2.77 micrograms was just large enough for them to see – the first time plutonium had ever been seen.

When Broughton found it, the plutonium sample was sitting in a clear plastic box labeled “First sample of Pu weighed. 2.7 µg” in the Hazardous Materials Facility. “This is the equivalent to the original moon rock,” he recalled. Despite a rigorous search, however, he was unable to find any other documentation showing the plutonium’s provenance – required for any museum to accept the plutonium sample as the first visible speck produced. In July 2014, Broughton asked Berkeley’s Department of Nuclear Engineering to help identify the metal. The team’s results indicate that the plutonium Broughton found was likely developed during the Manhattan Project by Cunningham and Werner.

Broughton and the nuclear engineering team are hopeful that the plutonium will be put on display at Berkeley, possibly in Seaborg’s historic lab. In the meantime, we are grateful that Broughton noticed the clear box and decided to pursue the plutonium’s story to its end!

For more on this important find, read this Scientific American article, Manhattan Project Plutonium, Lost to Obscurity, Recovered by Scientists.