Developing mass production methods of extracting uranium-235 from ore and/or creating plutonium.

Within a matter of weeks, North Korea could create enough weapons-grade plutonium from the fuel rods at Yongbyon to build about five bombs.

Dr. Seaborg's team went on to create plutonium, the element fueling the atomic bomb that destroyed Nagasaki, and eight other artificial elements.

The reprocessing does not create plutonium but recovers it so that it can be recycled as a source of energy.

"You create plutonium."

Department officials said, though, that the Federal Government taboo, dating from the "atoms for peace" era, was to avoid creating military plutonium in civilian plants, not consuming it.

In addition to a uranium pile, the Confederates also succeeded in creating plutonium (called "jovium") and neptunium (called "saturnium").

Using similar techniques, Dr. Seaborg's group went on to create plutonium, the artificial element in the atomic bomb that destroyed Nagasaki in 1945.

The scientists at the Berkeley conference envisioned creating plutonium in nuclear reactors where uranium-238 atoms absorbed neutrons that had been emitted from fissioning uranium-235 atoms.

The plutonium from a power reactor tends to have a greater amount of Pu-241 than the plutonium generated by the lower burnup operations designed to create weapons-grade plutonium.