Hang around on this planet long enough and some pretty strange tales are bound to come your way. A while back, one strange tale was sent in by reader Batshitbox. It’s the strange tale of the very first measurable sample of Plutonium 239 and how it was lost, then found again. All thanks to some quick thinking by a University of California employee that saved it from potential destruction.
In February 1941, a young physicist at the University of California, Berkeley named Glenn Seaborg and his cohorts, Arthur Wahl and Joseph Kennedy, were hanging out in Room 307 at the Gilman Hall on the UC Berkeley campus bombarding Uranium with deuterons in the 60-inch cyclotron. You know, what young people in the early 1940s did all the time. They noticed that the resulting element was something new. The new element had 94 protons and so they called it Element 94. Soon they would give it the snazzy name, “Plutonium”. (Ironically, if this happened today they would have named it something else since Pluto is no loner a planet.)
For the next year and a half, the guys studied their new element. Soon it became apparent that if they were to really do something worthwhile they would need a measurable amount. So, they bombarded several kilograms of Uranium until they could extract 2.77 micrograms of Plutonium. They then preserved this sample by sealing it in a glass tube.
That glass tube went on display at the UC Berkeley Lawrence Hall of Science until it was moved in 2007 to the Environmental, Health, and Safety department. There, it was put in a box and labeled “First sample of Pu weighed. 2.7 ug” and given a sample number S338. It was locked away in a safe and promptly forgotten.
In 2008, UC Berkeley Health Physicist, Phil Broughton, saw it and thought it was significant enough to bother the nation’s leading museums to see if they wanted to display it. The Smithsonian said they would need proof that it really was what the box claimed it to be. Unfortunately, all the paperwork proving what it was had been tossed along the way. How do you prove this is the sample that Seaborg and his team created 67 years ago? It went back on the shelf and was promptly forgotten.
Fast forward to June 2014. The Nuclear Engineering department at UC Berkeley found out about the sample, no doubt from rumors heard in the dark alleys of Berkeley, and wanted to try to figure out if the sample was Seaborg’s or not. They had a theory and if they could make it work, they would be heroes of the people.
They did not want to damage the sample, so they came up with a nondestructive way to test the sample. You see, Plutonium extracted from nuclear power reactors contains Plutionium 241 which decays to Americium 241. Even the processed Plutonium used in weapons still contains trace amounts of Plutonium 241. So, the nuclear engineering geeks put the sample up to some detectors and found no traces of Americium 241. If they had found any Americium 241 or Plutonium 241, the sample would have come from a nuclear reactor and not by the method described by Seaborg.
What they found was…nothing. Just Plutonium 239. They then determined the mass of the sample and found it to be consistent with what you would expect after six decades of storage. Therefore, it was determine this was Seaborg’s famous sample. It is now on display in Seaborg’s old office at UC Berkeley. Hopefully to never be lost again.
Source: Seaborg’s Plutonium? by Eric B. Norman, Keenan J. Thomas, Kristina Telhami*; Department of Nuclear Engineering, University of California, Berkeley, CA 94720