As the person who sent the link to me said, “this is [just] really cool.”

Nuclear archaeology has solved the mystery of a jug of plutonium that was found sealed inside a safe dug up as workers cleaned up an early Hanford burial ground.

Science showed the plutonium was historic: Researchers at the Department of Energy’s Pacific Northwest National Laboratory in Richland traced its origins to the first batch of weapons-grade materials ever processed at Hanford.

It’s also the second oldest known man-made plutonium 239, said Jon Schwantes, a PNNL senior research scientist who led the investigation. The oldest is held in the Smithsonian.

The results of the investigation are not just historically significant. Schwantes believes the research also may have applications in the field of nuclear forensics and efforts to keep nations safe from terrorists.

When researchers received the plutonium, they suspected it came from the beginnings of the Atomic Age after the 586-square-mile Hanford nuclear reservation was created during World War II as the United States raced to make enough plutonium to make an atomic bomb.

Hanford’s B Reactor was built as the nation’s first production-scale reactor. It irradiated nuclear fuel that was sent to Hanford’s T Plant, the world’s first industrial-scale reprocessing facility, which chemically extracted the plutonium.