chain-reacting pile

With Fermi’s chain-reacting pile still undergoing its difficult gestation, for all they knew this was the only plutonium that would be seen for months, or even years.

Its chain-reacting pile went live at the beginning of November and within six weeks was producing plutonium by the milligram, and soon by the gram.

A chain-reacting pile would be more efficient but still existed only in theory, for Fermi’s most recent prototype had produced less than one neutron per fission—a definite fizzle.

But many scientists, though interested in atomic power, are more interested in the radioactive materials from the Oak Ridge chain-reacting pile.

When natural uranium is put in a chain-reacting pile, its U-235 atoms start splitting and yielding energy, "fission products" and free neutrons.