Scientists carefully transported a tiny amount of plutonium for analysis at the national laboratory.

Researchers compared the isotopic compositions of different plutoniums to determine their origins.

A yellow-brown layer of plutonium dioxide had formed on the metal's surface after it was briefly exposed to air.

Scientists prevented the detonation of a plutonium bomb hidden in the abandoned facility.

After years of negotiation, the government agreed to destroy its plutonium bombs under international supervision.