The jar contained the oldest known sample of the stuff

Jan 21, 2009 14:10 GMT  ·  By

The city of Hanford, in Washington State, houses the oldest nuclear processing sites, and is now known as the place where weapons-grade plutonium was found lying around the dump site, enclosed only in a very shaky safe box. The find, besides eliminating a threat, also completes a piece of history, as the sample now collected is the first batch of plutonium ever to undergo the process, which makes it a trademark of the 20th century.

The site was constructed in 1943, as American authorities realized the necessity of building a processing center to support their expanding nuclear fission research that eventually led to the development of the nuclear bomb. The reservation was also used to produce weapons-grade plutonium for the Trinity test, the first detonation of a nuclear device, just three weeks before the infamous attacks on Hiroshima and Nagasaki, in Japan.

Hanford was known for 40 years as the “dirtiest place on Earth,” due to the fact that sloppy construction work on the part of the contractors resulted in constant leaks and infiltration of heavy elements into the ground, in pits and other spaces under the concrete floors.

Now, researchers at the Pacific Northwest National Laboratory in Richland, Washington, led by Jon Schwantes, have managed to discover the old safe at the bottom of a pit, and found inside some 400 milligrams of plutonium 239, the kind used for nuclear weapons. Because the chemical naturally decays to uranium over time, his team has been able to analyze the sample and conclude that it dates back to 1946, with an accuracy of 4.5 years.

Shuffling through old documents, the investigators have learned that, when the Hanford plant was first opened, it housed 4 of the 11 plutonium reactors in the US. They have also managed to find out the fact that the plant ran on fuel brought from somewhere else during the inauguration ceremony, before producing its own. The sample was tracked back to the X-10 reactor at Oak Ridge, in Tennessee, which made it the first weapons-grade plutonium amount ever produced.

“From the historical records, it looks as if they've got it right. But the puzzling thing is, why didn't this plutonium make it into the bomb?” Southampton University nuclear history expert John Simpson asks. He says that it's very weird that the first usable sample was buried instead of being used in the Manhattan Project, which dealt with the creation of the anti-Japanese atomic bomb.