Albert Filop, who worked as a researcher for Eastman Kodak, said the uranium was alloyed with aluminum in plates sealed in sleeves that weren't moved for three decades, CNN reported Wednesday.
Filop said the fuel totaled only 3.5 pounds, a quantity experts said was less than one-tenth of what is needed to make a crude nuclear device.
For more than 30 years, Kodak had a contraption called a Californium neutron flux multiplier, or CFX, beneath Building 82 at its labs near Rochester, N.Y.
The device, about the size of a refrigerator, was used to create a beam of neutrons for scanning and testing other materials.
Kodak did not have armed guards to protect the material but Filop said security procedures were in place to prevent any unauthorized access to the uranium.
It was turned over to the U.S. government in 2007 under heavy security.
A spokesman for the Nuclear Regulatory Commission said Kodak's uranium was highly enriched to a level approaching 93.4 percent.
Kodak said it never intended to hide the CFX which was licensed by both state and federal officials.
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