AW: AW: [ RadSafe ] FW: Nuclear Fuel Recycling

Strickert, Rick rstrickert at
Fri Jul 10 17:38:55 CDT 2009

marco bähler wrote: john gofman, co-inventor of pu.

John Gofman was not the "co-inventor of pu".  

Glenn Seaborg's graduate student, Arthur C. Wahl, first successfully separated and identified plutonium (as the isotope Pu-238) during February 23-25, 1941.  

On March 6, 1941, a sample of neptunium-239, mixed with a La/Ce carrier, was separated from 1.2 kilograms of irradiated uranyl nitrate hexahydrate and left to decay into plutonium-239.  Because of interferences from the carrier in trying to make neutron-induced fission cross-section measurements, on May 12, 1941, Art Wahl, still a grad student, redissolved the Pu-239 sample and used peroxydisulfate to convert the plutonium to a fluoride-soluble oxidation state while eliminating the La/Ce carriers by fluoride precipitation.  Wahl then reduced and co-precipitated the 0.5 microgram of plutonium with 0.2 milligram cerium as a fluoride.  This near-carrier-free sample enabled accurate measurements to be made of the Pu-239 half-life, alpha energy, and fission cross-section.  

In between testing, this sample of Pu-239 was stored in a cigar box, originally belonging to Prof. G.N. Lewis.  The cigar box and the plutonium sample now are on display at the Smithsonian Institution.  It is the oldest known collection of plutonium-239 in the world (

Rick Strickert
Austin, TX

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