The new research published by a DOE Los Alamos National Laboratory team from New Mexico in Friday's journal Science has scientific leaders calling for new evaluations of how plutonium is handled. That discovery, by a DOE team from Lawrence Livermore National Laboratory in Northern California in 1997, was the first evidence that plutonium did not stay put in the environment. The finding also may cause scientists to rethink plans for storing plutonium at Yucca Mountain outside Las Vegas, if the repository is approved to hold the nation's high level nuclear waste.
Plutonium is a radioactive metal made in nuclear reactors and used in atomic bombs.
At the time the scientists reported that the plutonium apparently rode microscopic particles known as colloids from the site of a 1968 nuclear experiment. In the presence of water, the Los Alamos scientific team discovered, a chemical change occurs in the plutonium and oxygen molecules over time that makes the radioactive element dissolve in water more easily. Before the discovery, scientists believed that plutonium dioxide, plutonium's version of ordinary rust, was the most stable form for long-term storage. Scientists working with the material for decades missed the change in molecules because it is so subtle, Haschke said. That could explain the surprise the DOE scientists expressed when they found the plutonium a mile away from the Test Site's crater, he said.